diff --git a/mozilla/content/base/src/nsDocument.cpp b/mozilla/content/base/src/nsDocument.cpp
index 6b0f249fc26..f08a584b2e0 100644
--- a/mozilla/content/base/src/nsDocument.cpp
+++ b/mozilla/content/base/src/nsDocument.cpp
@@ -2692,7 +2692,7 @@ PRBool    nsDocument::SetProperty(JSContext *aContext, JSObject *aObj, jsval aID
     mPropName.Assign(JS_GetStringChars(JS_ValueToString(aContext, aID)));
     if (mPropName.Length() > 2)
       mPrefix.Assign(mPropName.GetUnicode(), 2);
-    if (mPrefix == "on") {
+    if (mPrefix.Equals("on")) {
       nsCOMPtr<nsIAtom> atom = getter_AddRefs(NS_NewAtom(mPropName));
       nsIEventListenerManager *mManager = nsnull;
 
diff --git a/mozilla/content/base/src/nsDocumentEncoder.cpp b/mozilla/content/base/src/nsDocumentEncoder.cpp
index a88798c9954..a1de491b977 100644
--- a/mozilla/content/base/src/nsDocumentEncoder.cpp
+++ b/mozilla/content/base/src/nsDocumentEncoder.cpp
@@ -173,7 +173,7 @@ nsTextEncoder::EncodeToString(nsString& aOutputString)
   {
     nsString buffer;
 
-    if (mMimeType == "text/xif")
+    if (mMimeType.Equals("text/xif"))
     {
       mDocument->CreateXIF(aOutputString, mSelection);
       return NS_OK;
@@ -192,7 +192,7 @@ nsTextEncoder::EncodeToString(nsString& aOutputString)
     {
       nsIHTMLContentSink* sink = nsnull;
 
-      if (mMimeType == "text/html")
+      if (mMimeType.Equals("text/html"))
         rv = NS_New_HTML_ContentSinkStream(&sink, &aOutputString, mFlags);
 
       else  // default to text/plain
@@ -249,7 +249,7 @@ nsTextEncoder::EncodeToStream(nsIOutputStream* aStream)
     if (NS_SUCCEEDED(rv)) {
       nsIHTMLContentSink* sink = nsnull;
 
-      if (mMimeType == "text/html")
+      if (mMimeType.Equals("text/html"))
         rv = NS_New_HTML_ContentSinkStream(&sink, aStream, charset, mFlags);
 
       else
diff --git a/mozilla/content/base/src/nsGenericElement.cpp b/mozilla/content/base/src/nsGenericElement.cpp
index 8e57a97ff54..617d01cc039 100644
--- a/mozilla/content/base/src/nsGenericElement.cpp
+++ b/mozilla/content/base/src/nsGenericElement.cpp
@@ -1296,7 +1296,7 @@ nsGenericElement::SetProperty(JSContext *aContext, JSObject *aObj, jsval aID, js
     propName.Assign(JS_GetStringChars(JS_ValueToString(aContext, aID)));
     if (propName.Length() > 2) 
       prefix.Assign(propName.GetUnicode(), 2);
-    if (prefix == "on") {
+    if (prefix.Equals("on")) {
       nsCOMPtr<nsIAtom> atom = getter_AddRefs(NS_NewAtom(propName));
       nsIEventListenerManager *manager = nsnull;
 
diff --git a/mozilla/content/events/src/nsEventStateManager.cpp b/mozilla/content/events/src/nsEventStateManager.cpp
index e38f135c9bb..48dd730dd44 100644
--- a/mozilla/content/events/src/nsEventStateManager.cpp
+++ b/mozilla/content/events/src/nsEventStateManager.cpp
@@ -1802,7 +1802,7 @@ nsEventStateManager::GetNextTabbableContent(nsIContent* aParent, nsIContent* aCh
         if (focusable) {
           nsAutoString value;
           child->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, value);
-          if (value != "true")
+          if (!value.Equals("true"))
             disabled = PR_FALSE;
         }
       }
diff --git a/mozilla/content/html/content/src/nsHTMLInputElement.cpp b/mozilla/content/html/content/src/nsHTMLInputElement.cpp
index 3886cd840a5..0af8e852f0b 100644
--- a/mozilla/content/html/content/src/nsHTMLInputElement.cpp
+++ b/mozilla/content/html/content/src/nsHTMLInputElement.cpp
@@ -557,7 +557,7 @@ nsHTMLInputElement::GetChecked(PRBool* aValue)
     }
   }
   
-  if (value == "1")
+  if (value.Equals("1"))
     *aValue = PR_TRUE;
   else
     *aValue = PR_FALSE;
diff --git a/mozilla/content/html/content/src/nsHTMLOptionElement.cpp b/mozilla/content/html/content/src/nsHTMLOptionElement.cpp
index 2aae9a5fe59..ff6dc018b9b 100644
--- a/mozilla/content/html/content/src/nsHTMLOptionElement.cpp
+++ b/mozilla/content/html/content/src/nsHTMLOptionElement.cpp
@@ -260,7 +260,7 @@ nsHTMLOptionElement::GetSelected(PRBool* aValue)
       nsString value;
       value.Append(indx, 10); // Save the index in base 10
       formControlFrame->GetProperty(nsHTMLAtoms::selected, value);
-      if (value == "1")
+      if (value.Equals("1"))
         *aValue = PR_TRUE;
       else
         *aValue = PR_FALSE;
diff --git a/mozilla/content/html/document/src/nsHTMLContentSink.cpp b/mozilla/content/html/document/src/nsHTMLContentSink.cpp
index 9abeb3fb297..5fcf1193cf6 100644
--- a/mozilla/content/html/document/src/nsHTMLContentSink.cpp
+++ b/mozilla/content/html/document/src/nsHTMLContentSink.cpp
@@ -3557,7 +3557,7 @@ HTMLContentSink::ProcessStyleLink(nsIHTMLContent* aElement,
 				if (0 == mimeType.Length()) {
 					nsString extension;
 					aHref.Right(extension, 4);
-					if (extension == ".css") {
+					if (extension.Equals(".css")) {
 						isStyleSheet = PR_TRUE;			// strict mode + no mime type + '.css' extension
 					}
 				}
diff --git a/mozilla/content/html/document/src/nsHTMLDocument.cpp b/mozilla/content/html/document/src/nsHTMLDocument.cpp
index dfba2150e54..fdfd485f07b 100644
--- a/mozilla/content/html/document/src/nsHTMLDocument.cpp
+++ b/mozilla/content/html/document/src/nsHTMLDocument.cpp
@@ -431,7 +431,7 @@ nsHTMLDocument::StartDocumentLoad(const char* aCommand,
 
     NS_RELEASE(lastModKey);
     if (NS_SUCCEEDED(rv)) {
-      lastModified = lastModHeader;
+      lastModified.Assign(lastModHeader);
       SetLastModified(lastModified);
     }
 
@@ -445,7 +445,7 @@ nsHTMLDocument::StartDocumentLoad(const char* aCommand,
 
     NS_RELEASE(referrerKey);
     if (NS_SUCCEEDED(rv)) {
-      referrer = referrerHeader;
+      referrer.Assign(referrerHeader);
       SetReferrer(referrer);
     }
 
@@ -457,7 +457,7 @@ nsHTMLDocument::StartDocumentLoad(const char* aCommand,
       NS_RELEASE(contentTypeKey);
       if (NS_SUCCEEDED(rv)) {
         nsAutoString contentType;
-        contentType = contenttypeheader;
+        contentType.Assign(contenttypeheader);
         PRInt32 start = contentType.RFind("charset=", PR_TRUE ) ;
         if(kNotFound != start)
         {
diff --git a/mozilla/content/xbl/src/nsXBLBinding.cpp b/mozilla/content/xbl/src/nsXBLBinding.cpp
index e917b6a805f..e8bf0adf745 100644
--- a/mozilla/content/xbl/src/nsXBLBinding.cpp
+++ b/mozilla/content/xbl/src/nsXBLBinding.cpp
@@ -405,7 +405,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
     // in the excludes list.
     nsAutoString excludes;
     content->GetAttribute(kNameSpaceID_None, kExcludesAtom, excludes);
-    if (excludes != "*") {
+    if (!excludes.Equals("*")) {
       if (!excludes.IsEmpty()) {
         // Walk the children and ensure that all of them
         // are in the excludes array.
@@ -450,7 +450,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
       nsCOMPtr<nsIDOMAttr> attr(do_QueryInterface(attribute));
       nsAutoString name;
       attr->GetName(name);
-      if (name != "excludes") {
+      if (!name.Equals("excludes")) {
         nsAutoString value;
         nsCOMPtr<nsIDOMElement> element(do_QueryInterface(mBoundElement));
         element->GetAttribute(name, value);
@@ -504,7 +504,7 @@ nsXBLBinding::InstallEventHandlers(nsIContent* aBoundElement)
       nsAutoString type;
       child->GetAttribute(kNameSpaceID_None, kTypeAtom, type);
     
-      if (type != "") {
+      if (!type.IsEmpty()) {
         nsCOMPtr<nsIAtom> eventAtom = getter_AddRefs(NS_NewAtom(type));
         PRBool found = PR_FALSE;
         nsIID iid;
@@ -526,7 +526,7 @@ nsXBLBinding::InstallEventHandlers(nsIContent* aBoundElement)
             PRBool useCapture = PR_FALSE;
             nsAutoString capturer;
             child->GetAttribute(kNameSpaceID_None, kCapturerAtom, capturer);
-            if (capturer == "true")
+            if (capturer.Equals("true"))
               useCapture = PR_TRUE;
 
             // Add the event listener.
@@ -569,7 +569,7 @@ nsXBLBinding::GetBaseTag(nsIAtom** aResult)
   nsAutoString extends;
   mBinding->GetAttribute(kNameSpaceID_None, kExtendsAtom, extends);
 
-  if (extends != "") {
+  if (!extends.IsEmpty()) {
     // Obtain the namespace prefix.
     nsAutoString prefix;
     PRInt32 offset = extends.FindChar(kNameSpaceSeparator);
@@ -657,7 +657,7 @@ nsXBLBinding::AttributeChanged(nsIAtom* aAttribute, PRInt32 aNameSpaceID, PRBool
           // Construct a new text node and insert it.
           nsAutoString value;
           nsresult result = mBoundElement->GetAttribute(aNameSpaceID, aAttribute, value);
-          if (value != "") {
+          if (!value.IsEmpty()) {
             nsCOMPtr<nsIDOMText> textNode;
             nsCOMPtr<nsIDocument> doc;
             mBoundElement->GetDocument(*getter_AddRefs(doc));
@@ -731,7 +731,7 @@ nsXBLBinding::IsInExcludesList(nsIAtom* aTag, const nsString& aList)
   nsAutoString element;
   aTag->ToString(element);
 
-  if (aList == "*")
+  if (aList.Equals("*"))
       return PR_TRUE; // match _everything_!
 
   PRInt32 indx = aList.Find(element);
@@ -762,7 +762,7 @@ nsXBLBinding::ConstructAttributeTable(nsIContent* aElement)
   // ability to map one attribute to another.
   nsAutoString inherits;
   aElement->GetAttribute(kNameSpaceID_None, kInheritsAtom, inherits);
-  if (inherits != "") {
+  if (!inherits.IsEmpty()) {
     if (!mAttributeTable) {
         mAttributeTable = new nsSupportsHashtable(8);
     }
@@ -825,7 +825,7 @@ nsXBLBinding::ConstructAttributeTable(nsIContent* aElement)
         aElement->SetAttribute(kNameSpaceID_None, attribute, value, PR_TRUE);
         nsCOMPtr<nsIAtom> tag;
         aElement->GetTag(*getter_AddRefs(tag));
-        if ((tag.get() == kHTMLAtom) && (attribute.get() == kValueAtom) && value != "") {
+        if ((tag.get() == kHTMLAtom) && (attribute.get() == kValueAtom) && !value.IsEmpty()) {
           nsCOMPtr<nsIDOMText> textNode;
           nsCOMPtr<nsIDocument> doc;
           mBoundElement->GetDocument(*getter_AddRefs(doc));
@@ -873,21 +873,21 @@ nsXBLBinding::GetEventHandlerIID(nsIAtom* aName, nsIID* aIID, PRBool* aFound)
 PRBool
 nsXBLBinding::IsMouseHandler(const nsString& aName)
 {
-  return ((aName == "click") || (aName == "dblclick") || (aName=="mousedown") ||
-          (aName == "mouseover") || (aName == "mouseout") || (aName == "mouseup"));
+  return ((aName.Equals("click")) || (aName.Equals("dblclick")) || (aName.Equals("mousedown")) ||
+          (aName.Equals("mouseover")) || (aName.Equals("mouseout")) || (aName.Equals("mouseup")));
 }
 
 PRBool
 nsXBLBinding::IsKeyHandler(const nsString& aName)
 {
-  return ((aName == "keypress") || (aName == "keydown") || (aName == "keyup"));
+  return ((aName.Equals("keypress")) || (aName.Equals("keydown")) || (aName.Equals("keyup")));
 }
 
 PRBool
 nsXBLBinding::IsXULHandler(const nsString& aName)
 {
-  return ((aName == "create") || (aName == "destroy") || (aName=="broadcast") ||
-          (aName == "command") || (aName == "commandupdate") || (aName == "close"));
+  return ((aName.Equals("create")) || (aName.Equals("destroy")) || (aName.Equals("broadcast")) ||
+          (aName.Equals("command")) || (aName.Equals("commandupdate")) || (aName.Equals("close")));
 }
 
 NS_IMETHODIMP
diff --git a/mozilla/content/xbl/src/nsXBLEventHandler.cpp b/mozilla/content/xbl/src/nsXBLEventHandler.cpp
index 00e46f585c7..ead14f8a341 100644
--- a/mozilla/content/xbl/src/nsXBLEventHandler.cpp
+++ b/mozilla/content/xbl/src/nsXBLEventHandler.cpp
@@ -101,7 +101,7 @@ nsresult nsXBLEventHandler::HandleEvent(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::KeyUp(nsIDOMEvent* aKeyEvent)
 {
-  if (mEventName != "keyup")
+  if (!mEventName.Equals("keyup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
@@ -112,7 +112,7 @@ nsresult nsXBLEventHandler::KeyUp(nsIDOMEvent* aKeyEvent)
 
 nsresult nsXBLEventHandler::KeyDown(nsIDOMEvent* aKeyEvent)
 {
-  if (mEventName != "keydown")
+  if (!mEventName.Equals("keydown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
@@ -123,7 +123,7 @@ nsresult nsXBLEventHandler::KeyDown(nsIDOMEvent* aKeyEvent)
 
 nsresult nsXBLEventHandler::KeyPress(nsIDOMEvent* aKeyEvent)
 {
-  if (mEventName != "keypress")
+  if (!mEventName.Equals("keypress"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
@@ -134,7 +134,7 @@ nsresult nsXBLEventHandler::KeyPress(nsIDOMEvent* aKeyEvent)
    
 nsresult nsXBLEventHandler::MouseDown(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mousedown")
+  if (!mEventName.Equals("mousedown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -145,7 +145,7 @@ nsresult nsXBLEventHandler::MouseDown(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseUp(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mouseup")
+  if (!mEventName.Equals("mouseup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -156,7 +156,7 @@ nsresult nsXBLEventHandler::MouseUp(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseClick(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "click")
+  if (!mEventName.Equals("click"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -167,7 +167,7 @@ nsresult nsXBLEventHandler::MouseClick(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseDblClick(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "dblclick")
+  if (!mEventName.Equals("dblclick"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -178,7 +178,7 @@ nsresult nsXBLEventHandler::MouseDblClick(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseOver(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mouseover")
+  if (!mEventName.Equals("mouseover"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -189,7 +189,7 @@ nsresult nsXBLEventHandler::MouseOver(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseOut(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mouseout")
+  if (!mEventName.Equals("mouseout"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -200,7 +200,7 @@ nsresult nsXBLEventHandler::MouseOut(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::Action(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "command")
+  if (!mEventName.Equals("command"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("command"), aEvent);
@@ -209,7 +209,7 @@ nsresult nsXBLEventHandler::Action(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Create(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "create")
+  if (!mEventName.Equals("create"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("create"), aEvent);
@@ -218,7 +218,7 @@ nsresult nsXBLEventHandler::Create(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Close(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "close")
+  if (!mEventName.Equals("close"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("close"), aEvent);
@@ -227,7 +227,7 @@ nsresult nsXBLEventHandler::Close(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Broadcast(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "broadcast")
+  if (!mEventName.Equals("broadcast"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("broadcast"), aEvent);
@@ -236,7 +236,7 @@ nsresult nsXBLEventHandler::Broadcast(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::CommandUpdate(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "commandupdate")
+  if (!mEventName.Equals("commandupdate"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("commandupdate"), aEvent);
@@ -245,7 +245,7 @@ nsresult nsXBLEventHandler::CommandUpdate(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Destroy(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "destroy")
+  if (!mEventName.Equals("destroy"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("destroy"), aEvent);
diff --git a/mozilla/content/xbl/src/nsXBLService.cpp b/mozilla/content/xbl/src/nsXBLService.cpp
index 38801f40a3b..f73a1dce99f 100644
--- a/mozilla/content/xbl/src/nsXBLService.cpp
+++ b/mozilla/content/xbl/src/nsXBLService.cpp
@@ -340,7 +340,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
 {
   *aResult = nsnull;
 
-  if (aURLStr == nsCAutoString(""))
+  if (aURLStr.IsEmpty())
     return NS_ERROR_FAILURE;
 
   nsCOMPtr<nsIURL> uri;
@@ -379,7 +379,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
     child->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::name, value);
     
     // If no ref is specified just use this.
-    if ((bindingName == "") || (bindingName == value)) {
+    if ((bindingName.IsEmpty()) || (bindingName == value)) {
       // Make a new binding
       NS_NewXBLBinding(aResult);
 
@@ -388,7 +388,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
 
       // Check for the presence of an extends attribute
       child->GetAttribute(kNameSpaceID_None, kExtendsAtom, value);
-      if (value != "") {
+      if (!value.IsEmpty()) {
         // See if we are extending a builtin tag.
         nsCOMPtr<nsIAtom> tag;
         (*aResult)->GetBaseTag(getter_AddRefs(tag));
@@ -538,7 +538,7 @@ nsXBLService::StripWhitespaceNodes(nsIContent* aElement)
       nsAutoString result;
       text->CopyText(result);
       result.StripWhitespace();
-      if (result == "") {
+      if (result.IsEmpty()) {
         // This node contained nothing but whitespace.
         // Remove it from the content model.
         aElement->RemoveChildAt(i, PR_TRUE);
diff --git a/mozilla/content/xml/document/src/nsXMLContentSink.cpp b/mozilla/content/xml/document/src/nsXMLContentSink.cpp
index ffc6f92c8bd..16c30d16132 100644
--- a/mozilla/content/xml/document/src/nsXMLContentSink.cpp
+++ b/mozilla/content/xml/document/src/nsXMLContentSink.cpp
@@ -1960,7 +1960,7 @@ nsXMLContentSink::GetElementFactory(PRInt32 aNameSpaceID, nsIElementFactory** aR
   gNameSpaceManager->GetNameSpaceURI(aNameSpaceID, nameSpace);
 
   nsCAutoString progID = NS_ELEMENT_FACTORY_PROGID_PREFIX;
-  progID += nameSpace;
+  progID.Append(nameSpace);
 
   // Retrieve the appropriate factory.
   NS_WITH_SERVICE(nsIElementFactory, elementFactory, progID, &rv);
diff --git a/mozilla/content/xml/document/src/nsXMLDocument.cpp b/mozilla/content/xml/document/src/nsXMLDocument.cpp
index 2ffde668ce9..8896f72d138 100644
--- a/mozilla/content/xml/document/src/nsXMLDocument.cpp
+++ b/mozilla/content/xml/document/src/nsXMLDocument.cpp
@@ -276,7 +276,7 @@ nsXMLDocument::StartDocumentLoad(const char* aCommand,
      NS_RELEASE(contentTypeKey);
      if (NS_SUCCEEDED(rv)) {
 	nsAutoString contentType;
-	contentType = contenttypeheader;
+	contentType.Assign(contenttypeheader);
 	PRInt32 start = contentType.RFind("charset=", PR_TRUE ) ;
 	if(kNotFound != start)
 	{
diff --git a/mozilla/layout/base/nsCSSFrameConstructor.cpp b/mozilla/layout/base/nsCSSFrameConstructor.cpp
index 31985a5bb33..e2309996ace 100644
--- a/mozilla/layout/base/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/base/nsCSSFrameConstructor.cpp
@@ -2277,7 +2277,7 @@ nsCSSFrameConstructor::TableProcessChild(nsIPresShell*        aPresShell,
             nsString charData;
             domData->GetData(charData);
             charData = charData.StripWhitespace();
-            if ((charData.Length() <= 0) && (charData != " ")) { // XXX check this
+            if ((charData.Length() <= 0) && (!charData.Equals(" "))) { // XXX check this
               needCell = PR_FALSE;  // only contains whitespace, don't create cell
             }
             NS_RELEASE(domData);
@@ -4326,7 +4326,7 @@ nsCSSFrameConstructor::CreateAnonymousFrames(nsIPresShell*        aPresShell,
   const nsStyleUserInterface* ui= (const nsStyleUserInterface*)
       styleContext->GetStyleData(eStyleStruct_UserInterface);
 
-  if (ui->mBehavior != "") {
+  if (!ui->mBehavior.IsEmpty()) {
     // Get the XBL loader.
     nsresult rv;
     NS_WITH_SERVICE(nsIXBLService, xblService, "component://netscape/xbl", &rv);
@@ -4489,7 +4489,7 @@ nsCSSFrameConstructor::CreateAnonymousTreeCellFrames(nsIPresShell*        aPresS
   const nsStyleUserInterface* ui= (const nsStyleUserInterface*)
       styleContext->GetStyleData(eStyleStruct_UserInterface);
 
-  if (ui->mBehavior != "") {
+  if (!ui->mBehavior.IsEmpty()) {
     // Get the XBL loader.
     nsresult rv;
     NS_WITH_SERVICE(nsIXBLService, xblService, "component://netscape/xbl", &rv);
@@ -4577,7 +4577,7 @@ nsCSSFrameConstructor::ConstructXULFrame(nsIPresShell*            aPresShell,
           aStyleContext->GetStyleData(eStyleStruct_UserInterface);
 
       // Ensure that our XBL bindings are installed.
-      if (ui->mBehavior != "") {
+      if (!ui->mBehavior.IsEmpty()) {
         // Get the XBL loader.
         nsresult rv;
         NS_WITH_SERVICE(nsIXBLService, xblService, "component://netscape/xbl", &rv);
diff --git a/mozilla/layout/base/src/nsDocument.cpp b/mozilla/layout/base/src/nsDocument.cpp
index 6b0f249fc26..f08a584b2e0 100644
--- a/mozilla/layout/base/src/nsDocument.cpp
+++ b/mozilla/layout/base/src/nsDocument.cpp
@@ -2692,7 +2692,7 @@ PRBool    nsDocument::SetProperty(JSContext *aContext, JSObject *aObj, jsval aID
     mPropName.Assign(JS_GetStringChars(JS_ValueToString(aContext, aID)));
     if (mPropName.Length() > 2)
       mPrefix.Assign(mPropName.GetUnicode(), 2);
-    if (mPrefix == "on") {
+    if (mPrefix.Equals("on")) {
       nsCOMPtr<nsIAtom> atom = getter_AddRefs(NS_NewAtom(mPropName));
       nsIEventListenerManager *mManager = nsnull;
 
diff --git a/mozilla/layout/base/src/nsDocumentEncoder.cpp b/mozilla/layout/base/src/nsDocumentEncoder.cpp
index a88798c9954..a1de491b977 100644
--- a/mozilla/layout/base/src/nsDocumentEncoder.cpp
+++ b/mozilla/layout/base/src/nsDocumentEncoder.cpp
@@ -173,7 +173,7 @@ nsTextEncoder::EncodeToString(nsString& aOutputString)
   {
     nsString buffer;
 
-    if (mMimeType == "text/xif")
+    if (mMimeType.Equals("text/xif"))
     {
       mDocument->CreateXIF(aOutputString, mSelection);
       return NS_OK;
@@ -192,7 +192,7 @@ nsTextEncoder::EncodeToString(nsString& aOutputString)
     {
       nsIHTMLContentSink* sink = nsnull;
 
-      if (mMimeType == "text/html")
+      if (mMimeType.Equals("text/html"))
         rv = NS_New_HTML_ContentSinkStream(&sink, &aOutputString, mFlags);
 
       else  // default to text/plain
@@ -249,7 +249,7 @@ nsTextEncoder::EncodeToStream(nsIOutputStream* aStream)
     if (NS_SUCCEEDED(rv)) {
       nsIHTMLContentSink* sink = nsnull;
 
-      if (mMimeType == "text/html")
+      if (mMimeType.Equals("text/html"))
         rv = NS_New_HTML_ContentSinkStream(&sink, aStream, charset, mFlags);
 
       else
diff --git a/mozilla/layout/base/src/nsGenericElement.cpp b/mozilla/layout/base/src/nsGenericElement.cpp
index 8e57a97ff54..617d01cc039 100644
--- a/mozilla/layout/base/src/nsGenericElement.cpp
+++ b/mozilla/layout/base/src/nsGenericElement.cpp
@@ -1296,7 +1296,7 @@ nsGenericElement::SetProperty(JSContext *aContext, JSObject *aObj, jsval aID, js
     propName.Assign(JS_GetStringChars(JS_ValueToString(aContext, aID)));
     if (propName.Length() > 2) 
       prefix.Assign(propName.GetUnicode(), 2);
-    if (prefix == "on") {
+    if (prefix.Equals("on")) {
       nsCOMPtr<nsIAtom> atom = getter_AddRefs(NS_NewAtom(propName));
       nsIEventListenerManager *manager = nsnull;
 
diff --git a/mozilla/layout/events/src/nsEventStateManager.cpp b/mozilla/layout/events/src/nsEventStateManager.cpp
index e38f135c9bb..48dd730dd44 100644
--- a/mozilla/layout/events/src/nsEventStateManager.cpp
+++ b/mozilla/layout/events/src/nsEventStateManager.cpp
@@ -1802,7 +1802,7 @@ nsEventStateManager::GetNextTabbableContent(nsIContent* aParent, nsIContent* aCh
         if (focusable) {
           nsAutoString value;
           child->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, value);
-          if (value != "true")
+          if (!value.Equals("true"))
             disabled = PR_FALSE;
         }
       }
diff --git a/mozilla/layout/forms/nsFormControlHelper.cpp b/mozilla/layout/forms/nsFormControlHelper.cpp
index 794c1240485..97611db0cf3 100644
--- a/mozilla/layout/forms/nsFormControlHelper.cpp
+++ b/mozilla/layout/forms/nsFormControlHelper.cpp
@@ -111,7 +111,7 @@ void nsFormControlHelper::ForceDrawFrame(nsIPresContext* aPresContext, nsIFrame
 
 PRBool nsFormControlHelper::GetBool(const nsString& aValue)
 {
-  if (aValue == NS_STRING_TRUE)
+  if (aValue.Equals(NS_STRING_TRUE))
     return(PR_TRUE);
   else
     return (PR_FALSE);
diff --git a/mozilla/layout/forms/nsGfxButtonControlFrame.cpp b/mozilla/layout/forms/nsGfxButtonControlFrame.cpp
index dfe841f54e1..2c7f3aecf6c 100644
--- a/mozilla/layout/forms/nsGfxButtonControlFrame.cpp
+++ b/mozilla/layout/forms/nsGfxButtonControlFrame.cpp
@@ -481,7 +481,7 @@ nsGfxButtonControlFrame::ButtonLocalize(char* aKey, nsString& oVal)
     nsAutoString key(aKey);
     rv = bundle->GetStringFromName(key.GetUnicode(), getter_Copies(valUni));
     if (NS_SUCCEEDED(rv) && valUni) {
-      oVal = valUni;
+      oVal.Assign(valUni);
     } else {
       oVal.Truncate();
     }
diff --git a/mozilla/layout/forms/nsGfxCheckboxControlFrame.cpp b/mozilla/layout/forms/nsGfxCheckboxControlFrame.cpp
index 072835ddefa..b1f766add59 100644
--- a/mozilla/layout/forms/nsGfxCheckboxControlFrame.cpp
+++ b/mozilla/layout/forms/nsGfxCheckboxControlFrame.cpp
@@ -549,9 +549,9 @@ nsGfxCheckboxControlFrame::CheckStateToString ( CheckState inState, nsString& ou
 nsGfxCheckboxControlFrame::CheckState 
 nsGfxCheckboxControlFrame::StringToCheckState ( const nsString & aStateAsString )
 {
-  if ( aStateAsString == NS_STRING_TRUE )
+  if ( aStateAsString.Equals(NS_STRING_TRUE) )
     return eOn;
-  else if ( aStateAsString == NS_STRING_FALSE )
+  else if ( aStateAsString.Equals(NS_STRING_FALSE) )
     return eOff;
 
   // not true and not false means mixed
diff --git a/mozilla/layout/forms/nsGfxRadioControlFrame.cpp b/mozilla/layout/forms/nsGfxRadioControlFrame.cpp
index 1c45f866b56..3421411658c 100644
--- a/mozilla/layout/forms/nsGfxRadioControlFrame.cpp
+++ b/mozilla/layout/forms/nsGfxRadioControlFrame.cpp
@@ -125,7 +125,7 @@ nsGfxRadioControlFrame::SetAdditionalStyleContext(PRInt32 aIndex,
 NS_IMETHODIMP nsGfxRadioControlFrame::SetProperty(nsIPresContext* aPresContext, nsIAtom* aName, const nsString& aValue)
 {
   if (nsHTMLAtoms::checked == aName) {
-    PRBool state = (aValue == NS_STRING_TRUE) ? PR_TRUE : PR_FALSE;
+    PRBool state = (aValue.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
 
     // if there is no form than the radiobtn is an orphan
@@ -365,7 +365,7 @@ nsGfxRadioControlFrame::RestoreState(nsIPresContext* aPresContext, nsIPresState*
   mIsRestored = PR_TRUE;
   nsAutoString string;
   aState->GetStateProperty("checked", string);
-  PRBool state = (string == NS_STRING_TRUE) ? PR_TRUE : PR_FALSE;
+  PRBool state = (string.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
   SetRadioState(aPresContext, state); // sets mChecked
   mRestoredChecked = mChecked;
diff --git a/mozilla/layout/generic/nsObjectFrame.cpp b/mozilla/layout/generic/nsObjectFrame.cpp
index e8a72ac7b05..1db96d9bcb0 100644
--- a/mozilla/layout/generic/nsObjectFrame.cpp
+++ b/mozilla/layout/generic/nsObjectFrame.cpp
@@ -650,7 +650,7 @@ nsObjectFrame::Reflow(nsIPresContext*          aPresContext,
 	if (classid.Find("clsid:") != -1)
 	{
             classid.Cut(0, 6); // Strip off the "clsid:". What's left is the class ID.
-	    bJavaPluginClsid = (classid == JAVA_CLASS_ID);
+	    bJavaPluginClsid = (classid.Equals(JAVA_CLASS_ID));
 	}
 
       // if we find "java:" in the class id, or we match the Java classid number, we have a java applet
@@ -702,7 +702,7 @@ nsObjectFrame::Reflow(nsIPresContext*          aPresContext,
       {
         // These are some builtin types that we know about for now.
         // (Eventually this will move somewhere else.)
-        if (classid == "browser")
+        if (classid.Equals("browser"))
         {
           widgetCID = kCAppShellCID;
 	        rv = InstantiateWidget(aPresContext, aMetrics, aReflowState, widgetCID);
diff --git a/mozilla/layout/html/base/src/nsObjectFrame.cpp b/mozilla/layout/html/base/src/nsObjectFrame.cpp
index e8a72ac7b05..1db96d9bcb0 100644
--- a/mozilla/layout/html/base/src/nsObjectFrame.cpp
+++ b/mozilla/layout/html/base/src/nsObjectFrame.cpp
@@ -650,7 +650,7 @@ nsObjectFrame::Reflow(nsIPresContext*          aPresContext,
 	if (classid.Find("clsid:") != -1)
 	{
             classid.Cut(0, 6); // Strip off the "clsid:". What's left is the class ID.
-	    bJavaPluginClsid = (classid == JAVA_CLASS_ID);
+	    bJavaPluginClsid = (classid.Equals(JAVA_CLASS_ID));
 	}
 
       // if we find "java:" in the class id, or we match the Java classid number, we have a java applet
@@ -702,7 +702,7 @@ nsObjectFrame::Reflow(nsIPresContext*          aPresContext,
       {
         // These are some builtin types that we know about for now.
         // (Eventually this will move somewhere else.)
-        if (classid == "browser")
+        if (classid.Equals("browser"))
         {
           widgetCID = kCAppShellCID;
 	        rv = InstantiateWidget(aPresContext, aMetrics, aReflowState, widgetCID);
diff --git a/mozilla/layout/html/content/src/nsHTMLInputElement.cpp b/mozilla/layout/html/content/src/nsHTMLInputElement.cpp
index 3886cd840a5..0af8e852f0b 100644
--- a/mozilla/layout/html/content/src/nsHTMLInputElement.cpp
+++ b/mozilla/layout/html/content/src/nsHTMLInputElement.cpp
@@ -557,7 +557,7 @@ nsHTMLInputElement::GetChecked(PRBool* aValue)
     }
   }
   
-  if (value == "1")
+  if (value.Equals("1"))
     *aValue = PR_TRUE;
   else
     *aValue = PR_FALSE;
diff --git a/mozilla/layout/html/content/src/nsHTMLOptionElement.cpp b/mozilla/layout/html/content/src/nsHTMLOptionElement.cpp
index 2aae9a5fe59..ff6dc018b9b 100644
--- a/mozilla/layout/html/content/src/nsHTMLOptionElement.cpp
+++ b/mozilla/layout/html/content/src/nsHTMLOptionElement.cpp
@@ -260,7 +260,7 @@ nsHTMLOptionElement::GetSelected(PRBool* aValue)
       nsString value;
       value.Append(indx, 10); // Save the index in base 10
       formControlFrame->GetProperty(nsHTMLAtoms::selected, value);
-      if (value == "1")
+      if (value.Equals("1"))
         *aValue = PR_TRUE;
       else
         *aValue = PR_FALSE;
diff --git a/mozilla/layout/html/document/src/nsHTMLContentSink.cpp b/mozilla/layout/html/document/src/nsHTMLContentSink.cpp
index 9abeb3fb297..5fcf1193cf6 100644
--- a/mozilla/layout/html/document/src/nsHTMLContentSink.cpp
+++ b/mozilla/layout/html/document/src/nsHTMLContentSink.cpp
@@ -3557,7 +3557,7 @@ HTMLContentSink::ProcessStyleLink(nsIHTMLContent* aElement,
 				if (0 == mimeType.Length()) {
 					nsString extension;
 					aHref.Right(extension, 4);
-					if (extension == ".css") {
+					if (extension.Equals(".css")) {
 						isStyleSheet = PR_TRUE;			// strict mode + no mime type + '.css' extension
 					}
 				}
diff --git a/mozilla/layout/html/document/src/nsHTMLDocument.cpp b/mozilla/layout/html/document/src/nsHTMLDocument.cpp
index dfba2150e54..fdfd485f07b 100644
--- a/mozilla/layout/html/document/src/nsHTMLDocument.cpp
+++ b/mozilla/layout/html/document/src/nsHTMLDocument.cpp
@@ -431,7 +431,7 @@ nsHTMLDocument::StartDocumentLoad(const char* aCommand,
 
     NS_RELEASE(lastModKey);
     if (NS_SUCCEEDED(rv)) {
-      lastModified = lastModHeader;
+      lastModified.Assign(lastModHeader);
       SetLastModified(lastModified);
     }
 
@@ -445,7 +445,7 @@ nsHTMLDocument::StartDocumentLoad(const char* aCommand,
 
     NS_RELEASE(referrerKey);
     if (NS_SUCCEEDED(rv)) {
-      referrer = referrerHeader;
+      referrer.Assign(referrerHeader);
       SetReferrer(referrer);
     }
 
@@ -457,7 +457,7 @@ nsHTMLDocument::StartDocumentLoad(const char* aCommand,
       NS_RELEASE(contentTypeKey);
       if (NS_SUCCEEDED(rv)) {
         nsAutoString contentType;
-        contentType = contenttypeheader;
+        contentType.Assign(contenttypeheader);
         PRInt32 start = contentType.RFind("charset=", PR_TRUE ) ;
         if(kNotFound != start)
         {
diff --git a/mozilla/layout/html/forms/src/nsFormControlHelper.cpp b/mozilla/layout/html/forms/src/nsFormControlHelper.cpp
index 794c1240485..97611db0cf3 100644
--- a/mozilla/layout/html/forms/src/nsFormControlHelper.cpp
+++ b/mozilla/layout/html/forms/src/nsFormControlHelper.cpp
@@ -111,7 +111,7 @@ void nsFormControlHelper::ForceDrawFrame(nsIPresContext* aPresContext, nsIFrame
 
 PRBool nsFormControlHelper::GetBool(const nsString& aValue)
 {
-  if (aValue == NS_STRING_TRUE)
+  if (aValue.Equals(NS_STRING_TRUE))
     return(PR_TRUE);
   else
     return (PR_FALSE);
diff --git a/mozilla/layout/html/forms/src/nsGfxAutoTextControlFrame.cpp b/mozilla/layout/html/forms/src/nsGfxAutoTextControlFrame.cpp
index bf5e947aee5..75d50807d2a 100644
--- a/mozilla/layout/html/forms/src/nsGfxAutoTextControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsGfxAutoTextControlFrame.cpp
@@ -191,7 +191,7 @@ void nsGfxAutoTextControlFrame::ReadAttributes(nsIContent* aContent)
 	if (NS_SUCCEEDED(aContent->GetAttribute(kNameSpaceID_HTML, nsHTMLAtoms::autocompletetype, val)))
 	{
 		if (! val.IsEmpty())
-			mUseBlurr = (val == "blurr");
+			mUseBlurr = (val.Equals("blurr"));
 	}
 }
 
diff --git a/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp b/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp
index dfe841f54e1..2c7f3aecf6c 100644
--- a/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp
@@ -481,7 +481,7 @@ nsGfxButtonControlFrame::ButtonLocalize(char* aKey, nsString& oVal)
     nsAutoString key(aKey);
     rv = bundle->GetStringFromName(key.GetUnicode(), getter_Copies(valUni));
     if (NS_SUCCEEDED(rv) && valUni) {
-      oVal = valUni;
+      oVal.Assign(valUni);
     } else {
       oVal.Truncate();
     }
diff --git a/mozilla/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp b/mozilla/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp
index 072835ddefa..b1f766add59 100644
--- a/mozilla/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsGfxCheckboxControlFrame.cpp
@@ -549,9 +549,9 @@ nsGfxCheckboxControlFrame::CheckStateToString ( CheckState inState, nsString& ou
 nsGfxCheckboxControlFrame::CheckState 
 nsGfxCheckboxControlFrame::StringToCheckState ( const nsString & aStateAsString )
 {
-  if ( aStateAsString == NS_STRING_TRUE )
+  if ( aStateAsString.Equals(NS_STRING_TRUE) )
     return eOn;
-  else if ( aStateAsString == NS_STRING_FALSE )
+  else if ( aStateAsString.Equals(NS_STRING_FALSE) )
     return eOff;
 
   // not true and not false means mixed
diff --git a/mozilla/layout/html/forms/src/nsGfxRadioControlFrame.cpp b/mozilla/layout/html/forms/src/nsGfxRadioControlFrame.cpp
index 1c45f866b56..3421411658c 100644
--- a/mozilla/layout/html/forms/src/nsGfxRadioControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsGfxRadioControlFrame.cpp
@@ -125,7 +125,7 @@ nsGfxRadioControlFrame::SetAdditionalStyleContext(PRInt32 aIndex,
 NS_IMETHODIMP nsGfxRadioControlFrame::SetProperty(nsIPresContext* aPresContext, nsIAtom* aName, const nsString& aValue)
 {
   if (nsHTMLAtoms::checked == aName) {
-    PRBool state = (aValue == NS_STRING_TRUE) ? PR_TRUE : PR_FALSE;
+    PRBool state = (aValue.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
 
     // if there is no form than the radiobtn is an orphan
@@ -365,7 +365,7 @@ nsGfxRadioControlFrame::RestoreState(nsIPresContext* aPresContext, nsIPresState*
   mIsRestored = PR_TRUE;
   nsAutoString string;
   aState->GetStateProperty("checked", string);
-  PRBool state = (string == NS_STRING_TRUE) ? PR_TRUE : PR_FALSE;
+  PRBool state = (string.Equals(NS_STRING_TRUE)) ? PR_TRUE : PR_FALSE;
 
   SetRadioState(aPresContext, state); // sets mChecked
   mRestoredChecked = mChecked;
diff --git a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
index 31985a5bb33..e2309996ace 100644
--- a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -2277,7 +2277,7 @@ nsCSSFrameConstructor::TableProcessChild(nsIPresShell*        aPresShell,
             nsString charData;
             domData->GetData(charData);
             charData = charData.StripWhitespace();
-            if ((charData.Length() <= 0) && (charData != " ")) { // XXX check this
+            if ((charData.Length() <= 0) && (!charData.Equals(" "))) { // XXX check this
               needCell = PR_FALSE;  // only contains whitespace, don't create cell
             }
             NS_RELEASE(domData);
@@ -4326,7 +4326,7 @@ nsCSSFrameConstructor::CreateAnonymousFrames(nsIPresShell*        aPresShell,
   const nsStyleUserInterface* ui= (const nsStyleUserInterface*)
       styleContext->GetStyleData(eStyleStruct_UserInterface);
 
-  if (ui->mBehavior != "") {
+  if (!ui->mBehavior.IsEmpty()) {
     // Get the XBL loader.
     nsresult rv;
     NS_WITH_SERVICE(nsIXBLService, xblService, "component://netscape/xbl", &rv);
@@ -4489,7 +4489,7 @@ nsCSSFrameConstructor::CreateAnonymousTreeCellFrames(nsIPresShell*        aPresS
   const nsStyleUserInterface* ui= (const nsStyleUserInterface*)
       styleContext->GetStyleData(eStyleStruct_UserInterface);
 
-  if (ui->mBehavior != "") {
+  if (!ui->mBehavior.IsEmpty()) {
     // Get the XBL loader.
     nsresult rv;
     NS_WITH_SERVICE(nsIXBLService, xblService, "component://netscape/xbl", &rv);
@@ -4577,7 +4577,7 @@ nsCSSFrameConstructor::ConstructXULFrame(nsIPresShell*            aPresShell,
           aStyleContext->GetStyleData(eStyleStruct_UserInterface);
 
       // Ensure that our XBL bindings are installed.
-      if (ui->mBehavior != "") {
+      if (!ui->mBehavior.IsEmpty()) {
         // Get the XBL loader.
         nsresult rv;
         NS_WITH_SERVICE(nsIXBLService, xblService, "component://netscape/xbl", &rv);
diff --git a/mozilla/layout/xbl/src/nsXBLBinding.cpp b/mozilla/layout/xbl/src/nsXBLBinding.cpp
index e917b6a805f..e8bf0adf745 100644
--- a/mozilla/layout/xbl/src/nsXBLBinding.cpp
+++ b/mozilla/layout/xbl/src/nsXBLBinding.cpp
@@ -405,7 +405,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
     // in the excludes list.
     nsAutoString excludes;
     content->GetAttribute(kNameSpaceID_None, kExcludesAtom, excludes);
-    if (excludes != "*") {
+    if (!excludes.Equals("*")) {
       if (!excludes.IsEmpty()) {
         // Walk the children and ensure that all of them
         // are in the excludes array.
@@ -450,7 +450,7 @@ nsXBLBinding::GenerateAnonymousContent(nsIContent* aBoundElement)
       nsCOMPtr<nsIDOMAttr> attr(do_QueryInterface(attribute));
       nsAutoString name;
       attr->GetName(name);
-      if (name != "excludes") {
+      if (!name.Equals("excludes")) {
         nsAutoString value;
         nsCOMPtr<nsIDOMElement> element(do_QueryInterface(mBoundElement));
         element->GetAttribute(name, value);
@@ -504,7 +504,7 @@ nsXBLBinding::InstallEventHandlers(nsIContent* aBoundElement)
       nsAutoString type;
       child->GetAttribute(kNameSpaceID_None, kTypeAtom, type);
     
-      if (type != "") {
+      if (!type.IsEmpty()) {
         nsCOMPtr<nsIAtom> eventAtom = getter_AddRefs(NS_NewAtom(type));
         PRBool found = PR_FALSE;
         nsIID iid;
@@ -526,7 +526,7 @@ nsXBLBinding::InstallEventHandlers(nsIContent* aBoundElement)
             PRBool useCapture = PR_FALSE;
             nsAutoString capturer;
             child->GetAttribute(kNameSpaceID_None, kCapturerAtom, capturer);
-            if (capturer == "true")
+            if (capturer.Equals("true"))
               useCapture = PR_TRUE;
 
             // Add the event listener.
@@ -569,7 +569,7 @@ nsXBLBinding::GetBaseTag(nsIAtom** aResult)
   nsAutoString extends;
   mBinding->GetAttribute(kNameSpaceID_None, kExtendsAtom, extends);
 
-  if (extends != "") {
+  if (!extends.IsEmpty()) {
     // Obtain the namespace prefix.
     nsAutoString prefix;
     PRInt32 offset = extends.FindChar(kNameSpaceSeparator);
@@ -657,7 +657,7 @@ nsXBLBinding::AttributeChanged(nsIAtom* aAttribute, PRInt32 aNameSpaceID, PRBool
           // Construct a new text node and insert it.
           nsAutoString value;
           nsresult result = mBoundElement->GetAttribute(aNameSpaceID, aAttribute, value);
-          if (value != "") {
+          if (!value.IsEmpty()) {
             nsCOMPtr<nsIDOMText> textNode;
             nsCOMPtr<nsIDocument> doc;
             mBoundElement->GetDocument(*getter_AddRefs(doc));
@@ -731,7 +731,7 @@ nsXBLBinding::IsInExcludesList(nsIAtom* aTag, const nsString& aList)
   nsAutoString element;
   aTag->ToString(element);
 
-  if (aList == "*")
+  if (aList.Equals("*"))
       return PR_TRUE; // match _everything_!
 
   PRInt32 indx = aList.Find(element);
@@ -762,7 +762,7 @@ nsXBLBinding::ConstructAttributeTable(nsIContent* aElement)
   // ability to map one attribute to another.
   nsAutoString inherits;
   aElement->GetAttribute(kNameSpaceID_None, kInheritsAtom, inherits);
-  if (inherits != "") {
+  if (!inherits.IsEmpty()) {
     if (!mAttributeTable) {
         mAttributeTable = new nsSupportsHashtable(8);
     }
@@ -825,7 +825,7 @@ nsXBLBinding::ConstructAttributeTable(nsIContent* aElement)
         aElement->SetAttribute(kNameSpaceID_None, attribute, value, PR_TRUE);
         nsCOMPtr<nsIAtom> tag;
         aElement->GetTag(*getter_AddRefs(tag));
-        if ((tag.get() == kHTMLAtom) && (attribute.get() == kValueAtom) && value != "") {
+        if ((tag.get() == kHTMLAtom) && (attribute.get() == kValueAtom) && !value.IsEmpty()) {
           nsCOMPtr<nsIDOMText> textNode;
           nsCOMPtr<nsIDocument> doc;
           mBoundElement->GetDocument(*getter_AddRefs(doc));
@@ -873,21 +873,21 @@ nsXBLBinding::GetEventHandlerIID(nsIAtom* aName, nsIID* aIID, PRBool* aFound)
 PRBool
 nsXBLBinding::IsMouseHandler(const nsString& aName)
 {
-  return ((aName == "click") || (aName == "dblclick") || (aName=="mousedown") ||
-          (aName == "mouseover") || (aName == "mouseout") || (aName == "mouseup"));
+  return ((aName.Equals("click")) || (aName.Equals("dblclick")) || (aName.Equals("mousedown")) ||
+          (aName.Equals("mouseover")) || (aName.Equals("mouseout")) || (aName.Equals("mouseup")));
 }
 
 PRBool
 nsXBLBinding::IsKeyHandler(const nsString& aName)
 {
-  return ((aName == "keypress") || (aName == "keydown") || (aName == "keyup"));
+  return ((aName.Equals("keypress")) || (aName.Equals("keydown")) || (aName.Equals("keyup")));
 }
 
 PRBool
 nsXBLBinding::IsXULHandler(const nsString& aName)
 {
-  return ((aName == "create") || (aName == "destroy") || (aName=="broadcast") ||
-          (aName == "command") || (aName == "commandupdate") || (aName == "close"));
+  return ((aName.Equals("create")) || (aName.Equals("destroy")) || (aName.Equals("broadcast")) ||
+          (aName.Equals("command")) || (aName.Equals("commandupdate")) || (aName.Equals("close")));
 }
 
 NS_IMETHODIMP
diff --git a/mozilla/layout/xbl/src/nsXBLEventHandler.cpp b/mozilla/layout/xbl/src/nsXBLEventHandler.cpp
index 00e46f585c7..ead14f8a341 100644
--- a/mozilla/layout/xbl/src/nsXBLEventHandler.cpp
+++ b/mozilla/layout/xbl/src/nsXBLEventHandler.cpp
@@ -101,7 +101,7 @@ nsresult nsXBLEventHandler::HandleEvent(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::KeyUp(nsIDOMEvent* aKeyEvent)
 {
-  if (mEventName != "keyup")
+  if (!mEventName.Equals("keyup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
@@ -112,7 +112,7 @@ nsresult nsXBLEventHandler::KeyUp(nsIDOMEvent* aKeyEvent)
 
 nsresult nsXBLEventHandler::KeyDown(nsIDOMEvent* aKeyEvent)
 {
-  if (mEventName != "keydown")
+  if (!mEventName.Equals("keydown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
@@ -123,7 +123,7 @@ nsresult nsXBLEventHandler::KeyDown(nsIDOMEvent* aKeyEvent)
 
 nsresult nsXBLEventHandler::KeyPress(nsIDOMEvent* aKeyEvent)
 {
-  if (mEventName != "keypress")
+  if (!mEventName.Equals("keypress"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMKeyEvent> keyEvent = do_QueryInterface(aKeyEvent);
@@ -134,7 +134,7 @@ nsresult nsXBLEventHandler::KeyPress(nsIDOMEvent* aKeyEvent)
    
 nsresult nsXBLEventHandler::MouseDown(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mousedown")
+  if (!mEventName.Equals("mousedown"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -145,7 +145,7 @@ nsresult nsXBLEventHandler::MouseDown(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseUp(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mouseup")
+  if (!mEventName.Equals("mouseup"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -156,7 +156,7 @@ nsresult nsXBLEventHandler::MouseUp(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseClick(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "click")
+  if (!mEventName.Equals("click"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -167,7 +167,7 @@ nsresult nsXBLEventHandler::MouseClick(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseDblClick(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "dblclick")
+  if (!mEventName.Equals("dblclick"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -178,7 +178,7 @@ nsresult nsXBLEventHandler::MouseDblClick(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseOver(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mouseover")
+  if (!mEventName.Equals("mouseover"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -189,7 +189,7 @@ nsresult nsXBLEventHandler::MouseOver(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::MouseOut(nsIDOMEvent* aMouseEvent)
 {
-  if (mEventName != "mouseout")
+  if (!mEventName.Equals("mouseout"))
     return NS_OK;
 
   nsCOMPtr<nsIDOMUIEvent> mouseEvent = do_QueryInterface(aMouseEvent);
@@ -200,7 +200,7 @@ nsresult nsXBLEventHandler::MouseOut(nsIDOMEvent* aMouseEvent)
 
 nsresult nsXBLEventHandler::Action(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "command")
+  if (!mEventName.Equals("command"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("command"), aEvent);
@@ -209,7 +209,7 @@ nsresult nsXBLEventHandler::Action(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Create(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "create")
+  if (!mEventName.Equals("create"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("create"), aEvent);
@@ -218,7 +218,7 @@ nsresult nsXBLEventHandler::Create(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Close(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "close")
+  if (!mEventName.Equals("close"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("close"), aEvent);
@@ -227,7 +227,7 @@ nsresult nsXBLEventHandler::Close(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Broadcast(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "broadcast")
+  if (!mEventName.Equals("broadcast"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("broadcast"), aEvent);
@@ -236,7 +236,7 @@ nsresult nsXBLEventHandler::Broadcast(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::CommandUpdate(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "commandupdate")
+  if (!mEventName.Equals("commandupdate"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("commandupdate"), aEvent);
@@ -245,7 +245,7 @@ nsresult nsXBLEventHandler::CommandUpdate(nsIDOMEvent* aEvent)
 
 nsresult nsXBLEventHandler::Destroy(nsIDOMEvent* aEvent)
 {
-  if (mEventName != "destroy")
+  if (!mEventName.Equals("destroy"))
     return NS_OK;
 
   ExecuteHandler(nsAutoString("destroy"), aEvent);
diff --git a/mozilla/layout/xbl/src/nsXBLService.cpp b/mozilla/layout/xbl/src/nsXBLService.cpp
index 38801f40a3b..f73a1dce99f 100644
--- a/mozilla/layout/xbl/src/nsXBLService.cpp
+++ b/mozilla/layout/xbl/src/nsXBLService.cpp
@@ -340,7 +340,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
 {
   *aResult = nsnull;
 
-  if (aURLStr == nsCAutoString(""))
+  if (aURLStr.IsEmpty())
     return NS_ERROR_FAILURE;
 
   nsCOMPtr<nsIURL> uri;
@@ -379,7 +379,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
     child->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::name, value);
     
     // If no ref is specified just use this.
-    if ((bindingName == "") || (bindingName == value)) {
+    if ((bindingName.IsEmpty()) || (bindingName == value)) {
       // Make a new binding
       NS_NewXBLBinding(aResult);
 
@@ -388,7 +388,7 @@ NS_IMETHODIMP nsXBLService::GetBinding(nsCAutoString& aURLStr, nsIXBLBinding** a
 
       // Check for the presence of an extends attribute
       child->GetAttribute(kNameSpaceID_None, kExtendsAtom, value);
-      if (value != "") {
+      if (!value.IsEmpty()) {
         // See if we are extending a builtin tag.
         nsCOMPtr<nsIAtom> tag;
         (*aResult)->GetBaseTag(getter_AddRefs(tag));
@@ -538,7 +538,7 @@ nsXBLService::StripWhitespaceNodes(nsIContent* aElement)
       nsAutoString result;
       text->CopyText(result);
       result.StripWhitespace();
-      if (result == "") {
+      if (result.IsEmpty()) {
         // This node contained nothing but whitespace.
         // Remove it from the content model.
         aElement->RemoveChildAt(i, PR_TRUE);
diff --git a/mozilla/layout/xml/document/src/nsXMLContentSink.cpp b/mozilla/layout/xml/document/src/nsXMLContentSink.cpp
index ffc6f92c8bd..16c30d16132 100644
--- a/mozilla/layout/xml/document/src/nsXMLContentSink.cpp
+++ b/mozilla/layout/xml/document/src/nsXMLContentSink.cpp
@@ -1960,7 +1960,7 @@ nsXMLContentSink::GetElementFactory(PRInt32 aNameSpaceID, nsIElementFactory** aR
   gNameSpaceManager->GetNameSpaceURI(aNameSpaceID, nameSpace);
 
   nsCAutoString progID = NS_ELEMENT_FACTORY_PROGID_PREFIX;
-  progID += nameSpace;
+  progID.Append(nameSpace);
 
   // Retrieve the appropriate factory.
   NS_WITH_SERVICE(nsIElementFactory, elementFactory, progID, &rv);
diff --git a/mozilla/layout/xml/document/src/nsXMLDocument.cpp b/mozilla/layout/xml/document/src/nsXMLDocument.cpp
index 2ffde668ce9..8896f72d138 100644
--- a/mozilla/layout/xml/document/src/nsXMLDocument.cpp
+++ b/mozilla/layout/xml/document/src/nsXMLDocument.cpp
@@ -276,7 +276,7 @@ nsXMLDocument::StartDocumentLoad(const char* aCommand,
      NS_RELEASE(contentTypeKey);
      if (NS_SUCCEEDED(rv)) {
 	nsAutoString contentType;
-	contentType = contenttypeheader;
+	contentType.Assign(contenttypeheader);
 	PRInt32 start = contentType.RFind("charset=", PR_TRUE ) ;
 	if(kNotFound != start)
 	{
diff --git a/mozilla/layout/xul/base/src/nsGrippyFrame.cpp b/mozilla/layout/xul/base/src/nsGrippyFrame.cpp
index 7c6138be844..011d0a5eaf0 100644
--- a/mozilla/layout/xul/base/src/nsGrippyFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsGrippyFrame.cpp
@@ -91,7 +91,7 @@ nsGrippyFrame::MouseClicked(nsIPresContext* aPresContext)
 	nsString value;
     if (NS_CONTENT_ATTR_HAS_VALUE == content->GetAttribute(kNameSpaceID_None, nsXULAtoms::state, value))
     {
-     if (value=="collapsed")
+     if (value.Equals("collapsed"))
        a = "open";
     }
 
diff --git a/mozilla/layout/xul/base/src/nsMenuBarFrame.cpp b/mozilla/layout/xul/base/src/nsMenuBarFrame.cpp
index 48731cb90dc..c900c472961 100644
--- a/mozilla/layout/xul/base/src/nsMenuBarFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsMenuBarFrame.cpp
@@ -611,7 +611,7 @@ nsMenuBarFrame::IsDisabled(nsIContent* aContent)
 {
   nsString disabled = "";
   aContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, disabled);
-  if (disabled == "true")
+  if (disabled.Equals("true"))
     return PR_TRUE;
   return PR_FALSE;
 }
diff --git a/mozilla/layout/xul/base/src/nsMenuFrame.cpp b/mozilla/layout/xul/base/src/nsMenuFrame.cpp
index 453171e7535..97dd05a4174 100644
--- a/mozilla/layout/xul/base/src/nsMenuFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsMenuFrame.cpp
@@ -233,7 +233,7 @@ nsMenuFrame::GetFrameForPoint(nsIPresContext* aPresContext,
     // This allows selective overriding for subcontent.
     nsAutoString value;
     content->GetAttribute(kNameSpaceID_None, nsXULAtoms::allowevents, value);
-    if (value == "true")
+    if (value.Equals("true"))
       return result;
   }
   const nsStyleDisplay* disp = (const nsStyleDisplay*)
@@ -407,7 +407,7 @@ PRBool nsMenuFrame::IsGenerated()
   if (child) {
     nsString genVal;
     child->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, genVal);
-    if (genVal == "")
+    if (genVal.IsEmpty())
       return PR_FALSE;
   }
 
@@ -426,7 +426,7 @@ nsMenuFrame::MarkAsGenerated()
   if (child) {
     nsAutoString genVal;
     child->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, genVal);
-    if (genVal == "")
+    if (genVal.IsEmpty())
       child->SetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, "true", PR_TRUE);
   }
 
@@ -468,7 +468,7 @@ nsMenuFrame::AttributeChanged(nsIPresContext* aPresContext,
 
   if (aAttribute == nsXULAtoms::open) {
     aChild->GetAttribute(kNameSpaceID_None, aAttribute, value);
-    if (value == "true")
+    if (value.Equals("true"))
       OpenMenuInternal(PR_TRUE);
     else
       OpenMenuInternal(PR_FALSE);
@@ -572,15 +572,15 @@ nsMenuFrame::OpenMenuInternal(PRBool aActivateFlag)
 
       
       if (onMenuBar) {
-        if (popupAnchor == "")
+        if (popupAnchor.IsEmpty())
           popupAnchor = "bottomleft";
-        if (popupAlign == "")
+        if (popupAlign.IsEmpty())
           popupAlign = "topleft";
       }
       else {
-        if (popupAnchor == "")
+        if (popupAnchor.IsEmpty())
           popupAnchor = "topright";
-        if (popupAlign == "")
+        if (popupAlign.IsEmpty())
           popupAlign = "topleft";
       }
 
@@ -837,15 +837,15 @@ nsMenuFrame::DidReflow(nsIPresContext* aPresContext,
       mMenuParent->IsMenuBar(onMenuBar);
 
     if (onMenuBar) {
-      if (popupAnchor == "")
+      if (popupAnchor.IsEmpty())
           popupAnchor = "bottomleft";
-      if (popupAlign == "")
+      if (popupAlign.IsEmpty())
           popupAlign = "topleft";
     }
     else {
-      if (popupAnchor == "")
+      if (popupAnchor.IsEmpty())
         popupAnchor = "topright";
-      if (popupAlign == "")
+      if (popupAlign.IsEmpty())
         popupAlign = "topleft";
     }
 
@@ -945,7 +945,7 @@ nsMenuFrame::Notify(nsITimer* aTimer)
     if (!mMenuOpen && mMenuParent) {
       nsAutoString active = "";
       mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, active);
-      if (active == "true") {
+      if (active.Equals("true")) {
         // We're still the active menu.
         OpenMenu(PR_TRUE);
       }
@@ -962,7 +962,7 @@ nsMenuFrame::IsDisabled()
 {
   nsAutoString disabled;
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, disabled);
-  if (disabled == "true")
+  if (disabled.Equals("true"))
     return PR_TRUE;
   return PR_FALSE;
 }
@@ -972,9 +972,9 @@ nsMenuFrame::UpdateMenuType(nsIPresContext* aPresContext)
 {
   nsAutoString value;
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::type, value);
-  if (value == "checkbox")
+  if (value.Equals("checkbox"))
     mType = eMenuType_Checkbox;
-  else if (value == "radio") {
+  else if (value.Equals("radio")) {
     mType = eMenuType_Radio;
 
     nsAutoString value;
@@ -999,7 +999,7 @@ nsMenuFrame::UpdateMenuSpecialState(nsIPresContext* aPresContext) {
 
   mContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::checked,
                          value);
-  newChecked = (value == "true");
+  newChecked = (value.Equals("true"));
 
   if (newChecked == mChecked) {
     /* checked state didn't change */
@@ -1093,7 +1093,7 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
 {
   nsString accelText;
   mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::acceltext, accelText);
-  if (accelText != "") {
+  if (!accelText.IsEmpty()) {
     // Just use this.
     aAccelString = accelText;
     return;
@@ -1137,7 +1137,7 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
 	  
   nsAutoString xulkey;
   keyElement->GetAttribute(nsAutoString("xulkey"), xulkey);
-  if (xulkey == "true") {
+  if (xulkey.Equals("true")) {
       // Set the default for the xul key modifier
 #ifdef XP_MAC
       commandValue = "true";
@@ -1150,24 +1150,24 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
   
   PRBool prependPlus = PR_FALSE;
 
-  if(commandValue != "" && commandValue != "false") {
+  if(!commandValue.IsEmpty() && !commandValue.Equals("false")) {
     prependPlus = PR_TRUE;
 	  aAccelString += "Ctrl"; // Hmmm. Kinda defeats the point of having an abstraction.
   }
 
-  if(controlValue != "" && controlValue != "false") {
+  if(!controlValue.IsEmpty() && !controlValue.Equals("false")) {
     prependPlus = PR_TRUE;
 	  aAccelString += "Ctrl";
   }
 
-  if(shiftValue != "" && shiftValue != "false") {
+  if(!shiftValue.IsEmpty() && !shiftValue.Equals("false")) {
     if (prependPlus)
       aAccelString += "+";
     prependPlus = PR_TRUE;
     aAccelString += "Shift";
   }
 
-  if (altValue != "" && altValue != "false") {
+  if (!altValue.IsEmpty() && !altValue.Equals("false")) {
 	  if (prependPlus)
       aAccelString += "+";
     prependPlus = PR_TRUE;
@@ -1175,14 +1175,14 @@ nsMenuFrame::BuildAcceleratorText(nsString& aAccelString)
   }
 
   keyChar.ToUpperCase();
-  if (keyChar != "") {
+  if (!keyChar.IsEmpty()) {
     if (prependPlus)
       aAccelString += "+";
     prependPlus = PR_TRUE;
     aAccelString += keyChar;
   }
 
-  if (aAccelString != "")
+  if (!aAccelString.IsEmpty())
     mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::acceltext, aAccelString, PR_FALSE);
 }
 
diff --git a/mozilla/layout/xul/base/src/nsMenuPopupFrame.cpp b/mozilla/layout/xul/base/src/nsMenuPopupFrame.cpp
index fdf99996e7d..a9fab278e91 100644
--- a/mozilla/layout/xul/base/src/nsMenuPopupFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsMenuPopupFrame.cpp
@@ -319,35 +319,35 @@ nsMenuPopupFrame :: AdjustPositionForAnchorAlign ( PRInt32* ioXPos, PRInt32* ioY
                                                     const nsString& aPopupAnchor, const nsString& aPopupAlign,
                                                     PRBool* outFlushWithTopBottom )
 {
-  if (aPopupAnchor == "topright" && aPopupAlign == "topleft") {
+  if (aPopupAnchor.Equals("topright") && aPopupAlign.Equals("topleft")) {
     *ioXPos += inParentRect.width;
   }
-  else if (aPopupAnchor == "topright" && aPopupAlign == "bottomright") {
+  else if (aPopupAnchor.Equals("topright") && aPopupAlign.Equals("bottomright")) {
     *ioXPos -= (mRect.width - inParentRect.width);
     *ioYPos -= mRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
-  else if (aPopupAnchor == "bottomright" && aPopupAlign == "bottomleft") {
+  else if (aPopupAnchor.Equals("bottomright") && aPopupAlign.Equals("bottomleft")) {
     *ioXPos += inParentRect.width;
     *ioYPos -= (mRect.height - inParentRect.height);
   }
-  else if (aPopupAnchor == "bottomright" && aPopupAlign == "topright") {
+  else if (aPopupAnchor.Equals("bottomright") && aPopupAlign.Equals("topright")) {
     *ioXPos -= (mRect.width - inParentRect.width);
     *ioYPos += inParentRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
-  else if (aPopupAnchor == "topleft" && aPopupAlign == "topright") {
+  else if (aPopupAnchor.Equals("topleft") && aPopupAlign.Equals("topright")) {
     *ioXPos -= mRect.width;
   }
-  else if (aPopupAnchor == "topleft" && aPopupAlign == "bottomleft") {
+  else if (aPopupAnchor.Equals("topleft") && aPopupAlign.Equals("bottomleft")) {
     *ioYPos -= mRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
-  else if (aPopupAnchor == "bottomleft" && aPopupAlign == "bottomright") {
+  else if (aPopupAnchor.Equals("bottomleft") && aPopupAlign.Equals("bottomright")) {
     *ioXPos -= mRect.width;
     *ioYPos -= (mRect.height - inParentRect.height);
   }
-  else if (aPopupAnchor == "bottomleft" && aPopupAlign == "topleft") {
+  else if (aPopupAnchor.Equals("bottomleft") && aPopupAlign.Equals("topleft")) {
     *ioYPos += inParentRect.height;
     *outFlushWithTopBottom = PR_TRUE;
   }
@@ -709,7 +709,7 @@ nsMenuPopupFrame::SyncViewWithFrame(nsIPresContext* aPresContext,
   
   nsAutoString shouldDisplay, menuActive;
   mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, menuActive);
-  if (menuActive != "true") {
+  if (!menuActive.Equals("true")) {
     mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menutobedisplayed, shouldDisplay);
     if ( shouldDisplay.Equals("true") )
       mContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menuactive, "true", PR_TRUE);
@@ -1221,7 +1221,7 @@ nsMenuPopupFrame::IsDisabled(nsIContent* aContent)
 {
   nsString disabled = "";
   aContent->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::disabled, disabled);
-  if (disabled == "true")
+  if (disabled.Equals("true"))
     return PR_TRUE;
   return PR_FALSE;
 }
diff --git a/mozilla/layout/xul/base/src/nsPopupSetFrame.cpp b/mozilla/layout/xul/base/src/nsPopupSetFrame.cpp
index 20101bb4d15..de1a72c4f3e 100644
--- a/mozilla/layout/xul/base/src/nsPopupSetFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsPopupSetFrame.cpp
@@ -336,9 +336,9 @@ nsPopupSetFrame::DidReflow(nsIPresContext* aPresContext,
     menuPopupContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::popupanchor, popupAnchor);
     menuPopupContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::popupalign, popupAlign);
 
-    if (popupAnchor == "")
+    if (popupAnchor.IsEmpty())
       popupAnchor = "bottomleft";
-    if (popupAlign == "")
+    if (popupAlign.IsEmpty())
       popupAlign = "topleft";
    
     ((nsMenuPopupFrame*)activeChild)->SyncViewWithFrame(aPresContext, popupAnchor, popupAlign, mElementFrame, mXPos, mYPos);
@@ -442,7 +442,7 @@ nsPopupSetFrame::CreatePopup(nsIFrame* aElementFrame, nsIContent* aPopupContent,
   // determine if this menu is a context menu and flag it
   nsIFrame* activeChild = GetActiveChild();
   nsCOMPtr<nsIMenuParent> childPopup ( do_QueryInterface(activeChild) );
-  if ( childPopup && aPopupType == "context" )
+  if ( childPopup && aPopupType.Equals("context") )
     childPopup->SetIsContextMenu(PR_TRUE);
 
   // Now we'll have it in our child frame list.
@@ -482,7 +482,7 @@ nsPopupSetFrame::MarkAsGenerated(nsIContent* aPopupContent)
     nsAutoString value;
     childContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, 
                                value);
-    if (value == "true") {
+    if (value.Equals("true")) {
       // Ungenerate this element.
       childContent->UnsetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated,
                                    PR_TRUE);
@@ -494,7 +494,7 @@ nsPopupSetFrame::MarkAsGenerated(nsIContent* aPopupContent)
   nsAutoString value;
   aPopupContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, 
                               value);
-  if (value != "true") {
+  if (!value.Equals("true")) {
     // Generate this element.
     aPopupContent->SetAttribute(kNameSpaceID_None, nsXULAtoms::menugenerated, "true",
                                 PR_TRUE);
diff --git a/mozilla/layout/xul/base/src/nsSliderFrame.cpp b/mozilla/layout/xul/base/src/nsSliderFrame.cpp
index be00123938a..c720cce32ce 100644
--- a/mozilla/layout/xul/base/src/nsSliderFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsSliderFrame.cpp
@@ -295,7 +295,7 @@ nsSliderFrame::IsHorizontal(nsIContent* scrollbar)
   nsAutoString value;
   if (NS_CONTENT_ATTR_HAS_VALUE == scrollbar->GetAttribute(kNameSpaceID_None, nsHTMLAtoms::align, value))
   {
-    if (value=="vertical")
+    if (value.Equals("vertical"))
       isHorizontal = PR_FALSE;
   }
 
diff --git a/mozilla/layout/xul/base/src/nsTitledButtonFrame.cpp b/mozilla/layout/xul/base/src/nsTitledButtonFrame.cpp
index fbd3e822c6e..210e19f262b 100644
--- a/mozilla/layout/xul/base/src/nsTitledButtonFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTitledButtonFrame.cpp
@@ -294,7 +294,7 @@ nsTitledButtonFrame::Init(nsIPresContext*  aPresContext,
   nsAutoString accesskey;
   mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey,
                          accesskey);
-  if (accesskey != "") {    
+  if (!accesskey.IsEmpty()) {    
 	  mAccesskeyIndex = mTitle.Find(accesskey, PR_TRUE);
 	  if (mAccesskeyIndex == -1) {
 		  nsString tmpstring = "(" ;
@@ -808,7 +808,7 @@ nsTitledButtonFrame::UpdateAccessUnderline()
     nsAutoString accesskey;
     mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey,
                            accesskey);
-    if (accesskey == "")
+    if (accesskey.IsEmpty())
         return;                     // our work here is done
     
     mAccesskeyIndex = mCroppedTitle.Find(accesskey, PR_TRUE);
@@ -1280,9 +1280,9 @@ nsTitledButtonFrame::MouseClicked (nsIPresContext* aPresContext)
 nsTitledButtonFrame::CheckState
 nsTitledButtonFrame :: StringToCheckState ( const nsString & aStateAsString )
 {
-  if ( aStateAsString == NS_STRING_TRUE )
+  if ( aStateAsString.Equals(NS_STRING_TRUE) )
     return eOn;
-  else if ( aStateAsString == NS_STRING_FALSE )
+  else if ( aStateAsString.Equals(NS_STRING_FALSE) )
     return eOff;
   
   // not true and not false means mixed
diff --git a/mozilla/layout/xul/base/src/nsToolboxFrame.cpp b/mozilla/layout/xul/base/src/nsToolboxFrame.cpp
index 1edbc83e4f0..1b61744b96a 100644
--- a/mozilla/layout/xul/base/src/nsToolboxFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsToolboxFrame.cpp
@@ -458,7 +458,7 @@ nsToolboxFrame::CalculateGrippies(nsIPresContext* aPresContext)
     value = "";
     childContent->GetAttribute(kNameSpaceID_None, kCollapsedAtom, value);
 
-    if (value == "true") {  // The bar is collapsed!
+    if (value.Equals("true")) {  // The bar is collapsed!
       nscoord grippyWidth;
       nscoord grippyHeight;
 
diff --git a/mozilla/layout/xul/base/src/nsTreeCellFrame.cpp b/mozilla/layout/xul/base/src/nsTreeCellFrame.cpp
index c842d827c72..48789d6cee7 100644
--- a/mozilla/layout/xul/base/src/nsTreeCellFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTreeCellFrame.cpp
@@ -84,7 +84,7 @@ nsTreeCellFrame::Init(nsIPresContext*  aPresContext,
   nsresult result = aContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::allowevents, attrValue);
   attrValue.ToLowerCase();
   PRBool allowEvents =  (result == NS_CONTENT_ATTR_NO_VALUE ||
-					    (result == NS_CONTENT_ATTR_HAS_VALUE && attrValue=="true"));
+					    (result == NS_CONTENT_ATTR_HAS_VALUE && attrValue.Equals("true")));
   SetAllowEvents(allowEvents);
 
   // Determine if we're a column header or not.
@@ -171,7 +171,7 @@ nsTreeCellFrame::GetFrameForPoint(nsIPresContext* aPresContext,
         // This allows selective overriding for subcontent.
         nsAutoString value;
         content->GetAttribute(kNameSpaceID_None, nsXULAtoms::allowevents, value);
-        if (value == "true")
+        if (value.Equals("true"))
           return result;
       }
     }
@@ -356,7 +356,7 @@ nsTreeCellFrame::ToggleOpenClose()
 	  nsAutoString attrValue;
     treeItem->GetAttribute("open", attrValue);
     attrValue.ToLowerCase();
-    PRBool isExpanded = (attrValue=="true");
+    PRBool isExpanded = (attrValue.Equals("true"));
     if (isExpanded)
 	  {
 		  // We're collapsing and need to remove frames from the flow.
@@ -391,7 +391,7 @@ nsTreeCellFrame::Open()
 	  nsAutoString attrValue;
     treeItem->GetAttribute("open", attrValue);
     attrValue.ToLowerCase();
-    PRBool isExpanded = (attrValue=="true");
+    PRBool isExpanded = (attrValue.Equals("true"));
     if (!isExpanded) {
 		  // We're expanding and need to add frames to the flow.
 		  treeItem->SetAttribute("open", "true");
@@ -420,7 +420,7 @@ nsTreeCellFrame::Close()
 	  nsAutoString attrValue;
     treeItem->GetAttribute("open", attrValue);
     attrValue.ToLowerCase();
-    PRBool isExpanded = (attrValue=="true");
+    PRBool isExpanded = (attrValue.Equals("true"));
     if (isExpanded) {
 		  // We're expanding and need to add frames to the flow.
 		  treeItem->RemoveAttribute("open");
diff --git a/mozilla/layout/xul/base/src/nsTreeFrame.cpp b/mozilla/layout/xul/base/src/nsTreeFrame.cpp
index 83836b7e4fe..a5c9d3648fa 100644
--- a/mozilla/layout/xul/base/src/nsTreeFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTreeFrame.cpp
@@ -491,7 +491,7 @@ nsTreeFrame::Init(nsIPresContext*  aPresContext,
   nsCOMPtr<nsIDOMElement> element = do_QueryInterface(mContent);
   element->GetAttribute("rows", value);
 
-  if (value != "") {
+  if (!value.IsEmpty()) {
     PRInt32 dummy;
     PRInt32 count = value.ToInteger(&dummy);
     mFixedRows = count;
@@ -512,7 +512,7 @@ nsTreeFrame::ContainsFlexibleColumn(PRInt32 aStartIndex, PRInt32 aEndIndex,
     if (colContent) {
       nsAutoString fixedValue;
       colContent->GetAttribute(kNameSpaceID_None, fixedAtom, fixedValue);
-      if (fixedValue != "true") {
+      if (!fixedValue.Equals("true")) {
         // We are a proportional column.
         if (aResult)
           *aResult = result;
diff --git a/mozilla/layout/xul/base/src/nsTreeRowFrame.cpp b/mozilla/layout/xul/base/src/nsTreeRowFrame.cpp
index 671a10357ea..c826dd5bf70 100644
--- a/mozilla/layout/xul/base/src/nsTreeRowFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTreeRowFrame.cpp
@@ -309,7 +309,7 @@ nsTreeRowFrame::HandleHeaderDragEvent(nsIPresContext* aPresContext,
     if (colContent) {
       nsAutoString fixedValue;
       colContent->GetAttribute(kNameSpaceID_None, fixedAtom, fixedValue);
-      if (fixedValue != "true") {
+      if (!fixedValue.Equals("true")) {
         // We are a proportional column and should be annotated with our current
         // width.
         PRInt32 colWidth = treeFrame->GetColumnWidth(i);
diff --git a/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp b/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp
index c332ca94d34..03a31d987fa 100644
--- a/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTreeRowGroupFrame.cpp
@@ -539,7 +539,7 @@ nsTreeRowGroupFrame::FindRowContentAtIndex(PRInt32& aIndex,
       nsCOMPtr<nsIAtom> openAtom = dont_AddRef(NS_NewAtom("open"));
       nsAutoString isOpen;
       childContent->GetAttribute(kNameSpaceID_None, openAtom, isOpen);
-      if (isOpen == "true") {
+      if (isOpen.Equals("true")) {
         // Find the <treechildren> node.
         PRInt32 childContentCount;
         nsCOMPtr<nsIContent> grandChild;
@@ -615,7 +615,7 @@ nsTreeRowGroupFrame::FindPreviousRowContent(PRInt32& aDelta, nsIContent* aUpward
       nsCOMPtr<nsIAtom> openAtom = dont_AddRef(NS_NewAtom("open"));
       nsAutoString isOpen;
       childContent->GetAttribute(kNameSpaceID_None, openAtom, isOpen);
-      if (isOpen == "true") {
+      if (isOpen.Equals("true")) {
         // Find the <treechildren> node.
         PRInt32 childContentCount;
         nsCOMPtr<nsIContent> grandChild;
@@ -683,7 +683,7 @@ nsTreeRowGroupFrame::ComputeTotalRowCount(PRInt32& aCount, nsIContent* aParent)
       nsCOMPtr<nsIContent> parent;
       childContent->GetParent(*getter_AddRefs(parent));
       parent->GetAttribute(kNameSpaceID_None, openAtom, isOpen);
-      if (isOpen == "true")
+      if (isOpen.Equals("true"))
       ComputeTotalRowCount(aCount, childContent);
     }
   }
@@ -1566,7 +1566,7 @@ nsTreeRowGroupFrame::ReflowScrollbar(nsIPresContext* aPresContext)
                                      nsXULAtoms::curpos, value);
     }
    
-    if (nukeScrollbar || (value == "0" && !mIsFull)) {
+    if (nukeScrollbar || (value.Equals("0") && !mIsFull)) {
       
       // clear the scrollbar out of the event state manager so that the
       // event manager doesn't send events to the destroyed scrollbar frames
diff --git a/mozilla/layout/xul/base/src/nsTreeTwistyListener.cpp b/mozilla/layout/xul/base/src/nsTreeTwistyListener.cpp
index d4f52cfc1cb..43be1c8abc0 100644
--- a/mozilla/layout/xul/base/src/nsTreeTwistyListener.cpp
+++ b/mozilla/layout/xul/base/src/nsTreeTwistyListener.cpp
@@ -88,11 +88,11 @@ nsTreeTwistyListener::MouseDown(nsIDOMEvent* aEvent)
 
   nsAutoString tagName;
   element->GetTagName(tagName);
-  if (tagName == "titledbutton") {
+  if (tagName.Equals("titledbutton")) {
     // Find out if we're the twisty.
     nsAutoString classAttr;
     element->GetAttribute("class", classAttr);
-    if (classAttr == "twisty") {
+    if (classAttr.Equals("twisty")) {
       // Retrieve the parent treeitem.
       nsCOMPtr<nsIDOMElement> treeItem;
       GetTreeItem(element, getter_AddRefs(treeItem));
@@ -107,7 +107,7 @@ nsTreeTwistyListener::MouseDown(nsIDOMEvent* aEvent)
 
       nsAutoString open;
       treeItem->GetAttribute("open", open);
-      if (open == "true")
+      if (open.Equals("true"))
         treeItem->RemoveAttribute("open");
       else treeItem->SetAttribute("open", "true");
     }
diff --git a/mozilla/layout/xul/base/src/nsXULTextFrame.cpp b/mozilla/layout/xul/base/src/nsXULTextFrame.cpp
index 5850cecf173..51ad54401f7 100644
--- a/mozilla/layout/xul/base/src/nsXULTextFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsXULTextFrame.cpp
@@ -139,7 +139,7 @@ nsXULTextFrame::Init(nsIPresContext*  aPresContext,
   nsAutoString accesskey;
   mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey,
                          accesskey);
-  if (accesskey != "") {   
+  if (!accesskey.IsEmpty()) {   
       if (!mAccessKeyInfo)
           mAccessKeyInfo = new nsAccessKeyInfo();
 
@@ -540,7 +540,7 @@ nsXULTextFrame::UpdateAccessUnderline()
     nsAutoString accesskey;
     mContent->GetAttribute(kNameSpaceID_None, nsXULAtoms::accesskey,
                            accesskey);
-    if (accesskey == "") {
+    if (accesskey.IsEmpty()) {
         if (mAccessKeyInfo) {
             delete mAccessKeyInfo;
             mAccessKeyInfo = nsnull;