diff --git a/mozilla/accessible/src/atk/nsHTMLLinkAccessibleWrap.cpp b/mozilla/accessible/src/atk/nsHTMLLinkAccessibleWrap.cpp
index 0a94cc7c480..6b6dc690194 100644
--- a/mozilla/accessible/src/atk/nsHTMLLinkAccessibleWrap.cpp
+++ b/mozilla/accessible/src/atk/nsHTMLLinkAccessibleWrap.cpp
@@ -169,15 +169,12 @@ NS_IMETHODIMP nsHTMLImageMapAccessible::GetURI(PRInt32 aIndex, nsIURI **aURI)
 
   nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
   if (content) {
-    nsCOMPtr<nsIDocument> doc;
-    if (NS_SUCCEEDED(content->GetDocument(getter_AddRefs(doc)))) {
-      nsCOMPtr<nsIURI> baseURI;
-      if (NS_SUCCEEDED(doc->GetBaseURL(getter_AddRefs(baseURI)))) {
-        nsCOMPtr<nsIDOMElement> area(do_QueryInterface(domNode));
-        nsAutoString hrefValue;
-        if (NS_SUCCEEDED(area->GetAttribute(NS_LITERAL_STRING("href"), hrefValue))) {
-          return NS_NewURI(aURI, hrefValue, nsnull, baseURI);
-        }
+    nsCOMPtr<nsIURI> baseURI;
+    if (NS_SUCCEEDED(content->GetBaseURL(getter_AddRefs(baseURI)))) {
+      nsCOMPtr<nsIDOMElement> area(do_QueryInterface(domNode));
+      nsAutoString hrefValue;
+      if (NS_SUCCEEDED(area->GetAttribute(NS_LITERAL_STRING("href"), hrefValue))) {
+        return NS_NewURI(aURI, hrefValue, nsnull, baseURI);
       }
     }
   }
diff --git a/mozilla/content/base/public/nsIContent.h b/mozilla/content/base/public/nsIContent.h
index 765211198ac..45f06babb06 100644
--- a/mozilla/content/base/public/nsIContent.h
+++ b/mozilla/content/base/public/nsIContent.h
@@ -55,6 +55,7 @@ class nsISupportsArray;
 class nsIDOMRange;
 class nsINodeInfo;
 class nsIEventListenerManager;
+class nsIURI;
 
 // IID for the nsIContent interface
 #define NS_ICONTENT_IID       \
@@ -484,6 +485,16 @@ public:
    */
   NS_IMETHOD GetListenerManager(nsIEventListenerManager** aResult) = 0;
 
+  /**
+   * Get the base URL for any relative URLs within this piece
+   * of content. Generally, this is the document's base URL,
+   * but certain content carries a local base for backward
+   * compatibility.
+   *
+   * @param aBaseURL the base URL [OUT]
+   */
+  NS_IMETHOD GetBaseURL(nsIURI** aBaseURL) const = 0;
+
   /**
    * This method is called when the parser finishes creating the element.  This
    * particularly means that it has done everything you would expect it to have
diff --git a/mozilla/content/base/public/nsIDocument.h b/mozilla/content/base/public/nsIDocument.h
index 5405ac94ca0..c476782340a 100644
--- a/mozilla/content/base/public/nsIDocument.h
+++ b/mozilla/content/base/public/nsIDocument.h
@@ -140,8 +140,9 @@ public:
   NS_IMETHOD GetDocumentLoadGroup(nsILoadGroup** aGroup) const = 0;
 
   /**
-   * Return the base URL for relative URLs in the document. May return
-   * null (or the document URL).
+   * Return the base URL for relative URLs in the document (the document url
+   * unless it's overridden by SetBaseURL, HTML <base> tags, etc.).  The
+   * returned URL could be null if there is no document URL.
    */
   NS_IMETHOD GetBaseURL(nsIURI** aURL) const = 0;
   NS_IMETHOD SetBaseURL(nsIURI* aURL) = 0;
diff --git a/mozilla/content/base/src/nsContentAreaDragDrop.cpp b/mozilla/content/base/src/nsContentAreaDragDrop.cpp
index 87646c8936c..1f12fdaf0e7 100644
--- a/mozilla/content/base/src/nsContentAreaDragDrop.cpp
+++ b/mozilla/content/base/src/nsContentAreaDragDrop.cpp
@@ -985,14 +985,12 @@ nsTransferableFactory::GetAnchorURL(nsIDOMNode* inNode, nsAString& outURL)
       if (value.Equals(NS_LITERAL_STRING("simple"))) {
         content->GetAttr(kNameSpaceID_XLink, nsHTMLAtoms::href, value);
         if (!value.IsEmpty()) {
-          nsCOMPtr<nsIXMLContent> xml(do_QueryInterface(inNode));
-          if (xml) {
-            nsCOMPtr<nsIURI> baseURI;
-            if (NS_SUCCEEDED(xml->GetXMLBaseURI(getter_AddRefs(baseURI)))) {
-              nsCAutoString absoluteSpec;
-              baseURI->Resolve(NS_ConvertUCS2toUTF8(value), absoluteSpec);
-              outURL = NS_ConvertUTF8toUCS2(absoluteSpec);
-            }
+          nsCOMPtr<nsIURI> baseURI;
+          content->GetBaseURL(getter_AddRefs(baseURI));
+          if (baseURI) {
+            nsCAutoString absoluteSpec;
+            baseURI->Resolve(NS_ConvertUCS2toUTF8(value), absoluteSpec);
+            CopyUTF8toUTF16(absoluteSpec, outURL);
           }
         }
       } else {
diff --git a/mozilla/content/base/src/nsGenericDOMDataNode.cpp b/mozilla/content/base/src/nsGenericDOMDataNode.cpp
index 76ced9333f6..906d27ec739 100644
--- a/mozilla/content/base/src/nsGenericDOMDataNode.cpp
+++ b/mozilla/content/base/src/nsGenericDOMDataNode.cpp
@@ -49,7 +49,7 @@
 #include "nsMutationEvent.h"
 #include "nsINameSpaceManager.h"
 #include "nsIDOM3Node.h"
-
+#include "nsIURI.h"
 #include "nsIPrivateDOMEvent.h"
 #include "nsIDOMEvent.h"
 #include "nsIDOMText.h"
@@ -287,23 +287,14 @@ nsGenericDOMDataNode::IsSupported(const nsAString& aFeature,
 nsresult
 nsGenericDOMDataNode::GetBaseURI(nsAString& aURI)
 {
-  aURI.Truncate();
-  nsresult rv = NS_OK;
+  nsCOMPtr<nsIURI> baseURI;
+  nsresult rv = GetBaseURL(getter_AddRefs(baseURI));
 
-  // DOM Data Node inherits the base from its parent element/document
-  nsCOMPtr<nsIDOM3Node> node;
-
-  nsIContent *parent_weak = GetParentWeak();
-
-  if (parent_weak) {
-    node = do_QueryInterface(parent_weak);
-  } else if (mDocument) {
-    node = do_QueryInterface(mDocument);
-  }
-
-  if (node) {
-    rv = node->GetBaseURI(aURI);
+  nsCAutoString spec;
+  if (NS_SUCCEEDED(rv) && baseURI) {
+    baseURI->GetSpec(spec);
   }
+  CopyUTF8toUTF16(spec, aURI);
 
   return rv;
 }
@@ -1069,6 +1060,23 @@ nsGenericDOMDataNode::DumpContent(FILE* out, PRInt32 aIndent,
 }
 #endif
 
+NS_IMETHODIMP
+nsGenericDOMDataNode::GetBaseURL(nsIURI** aURI) const
+{
+  // DOM Data Node inherits the base from its parent element/document
+  nsIContent* parent_weak = GetParentWeak();
+  if (parent_weak) {
+    return parent_weak->GetBaseURL(aURI);
+  }
+
+  if (mDocument) {
+    return mDocument->GetBaseURL(aURI);
+  }
+
+  *aURI = nsnull;
+  return NS_OK;
+}
+
 //----------------------------------------------------------------------
 
 // Implementation of the nsIDOMText interface
diff --git a/mozilla/content/base/src/nsGenericDOMDataNode.h b/mozilla/content/base/src/nsGenericDOMDataNode.h
index 8746da1c750..55c11a19fe4 100644
--- a/mozilla/content/base/src/nsGenericDOMDataNode.h
+++ b/mozilla/content/base/src/nsGenericDOMDataNode.h
@@ -54,6 +54,7 @@ class nsIDOMNodeList;
 class nsIFrame;
 class nsIDOMText;
 class nsINodeInfo;
+class nsURI;
 
 #define PARENT_BIT_RANGELISTS       ((PtrBits)0x1 << 0)
 #define PARENT_BIT_LISTENERMANAGER  ((PtrBits)0x1 << 1)
@@ -212,6 +213,7 @@ public:
   NS_IMETHOD_(PRBool) IsContentOfType(PRUint32 aFlags);
 
   NS_IMETHOD GetListenerManager(nsIEventListenerManager** aInstancePtrResult);
+  NS_IMETHOD GetBaseURL(nsIURI** aURI) const;
   NS_IMETHOD DoneCreatingElement();
 
   NS_IMETHOD GetNodeInfo(nsINodeInfo** aResult) const;
diff --git a/mozilla/content/base/src/nsGenericElement.cpp b/mozilla/content/base/src/nsGenericElement.cpp
index 7f0f88582f0..ded2a460b27 100644
--- a/mozilla/content/base/src/nsGenericElement.cpp
+++ b/mozilla/content/base/src/nsGenericElement.cpp
@@ -192,38 +192,7 @@ nsNode3Tearoff::GetBaseURI(nsAString& aURI)
 {
   nsCOMPtr<nsIURI> uri;
 
-  nsCOMPtr<nsIDocument> doc;
-  mContent->GetDocument(getter_AddRefs(doc));
-
-  // XML content can use the XML Base (W3C spec) way of setting the
-  // base per element. We look at this node and its ancestors until we
-  // find the first XML content and get it's base.
-  nsCOMPtr<nsIContent> content(mContent);
-
-  do {
-    nsCOMPtr<nsIXMLContent> xmlContent(do_QueryInterface(content));
-
-    if (xmlContent) {
-      xmlContent->GetXMLBaseURI(getter_AddRefs(uri));
-
-      break;
-    }
-
-    nsCOMPtr<nsIContent> parent;
-    content->GetParent(getter_AddRefs(parent));
-    content.swap(parent);
-  } while (content);
-
-  if (!uri && doc) {
-    // HTML document or for some reason there was no XML content in
-    // XML document
-
-    doc->GetBaseURL(getter_AddRefs(uri));
-
-    if (!uri) {
-      doc->GetDocumentURL(getter_AddRefs(uri));
-    }
-  }
+  mContent->GetBaseURL(getter_AddRefs(uri));
 
   nsCAutoString spec;
 
@@ -1315,16 +1284,6 @@ nsGenericElement::HasAttributes(PRBool* aReturn)
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsGenericElement::GetXMLBaseURI(nsIURI **aURI)
-{
-  NS_ENSURE_ARG_POINTER(aURI);
-
-  *aURI = nsnull;
-
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsGenericElement::GetAttributes(nsIDOMNamedNodeMap** aAttributes)
 {
@@ -2281,7 +2240,56 @@ nsGenericElement::StringToAttribute(nsIAtom* aAttribute,
 NS_IMETHODIMP
 nsGenericElement::GetBaseURL(nsIURI** aBaseURL) const
 {
-  return NS_ERROR_NOT_IMPLEMENTED;
+  nsCOMPtr<nsIDocument> doc = mDocument;
+
+  if (!doc) {
+    mNodeInfo->GetDocument(getter_AddRefs(doc));
+  }
+
+  // Our base URL depends on whether we have an xml:base attribute, as
+  // well as on whether any of our ancestors do.
+  nsCOMPtr<nsIURI> parentBase;
+  if (mParent) {
+    mParent->GetBaseURL(getter_AddRefs(parentBase));
+  } else if (doc) {
+    // No parent, so just use the document (we must be the root or not in the
+    // tree).
+    doc->GetBaseURL(getter_AddRefs(parentBase));
+  }
+  
+  // Now check for an xml:base attr 
+  nsAutoString value;
+  nsresult rv = GetAttr(kNameSpaceID_XML, nsHTMLAtoms::base, value);
+  if (rv != NS_CONTENT_ATTR_HAS_VALUE) {
+    // No xml:base, so we just use the parent's base URL
+    NS_IF_ADDREF(*aBaseURL = parentBase);
+    return NS_OK;
+  }
+
+  nsCAutoString charset;
+  if (doc) {
+    doc->GetDocumentCharacterSet(charset);
+  }
+
+  nsCOMPtr<nsIURI> ourBase;
+  rv = NS_NewURI(getter_AddRefs(ourBase), value, charset.get(), parentBase);
+  if (NS_SUCCEEDED(rv)) {
+    // do a security check, almost the same as nsDocument::SetBaseURL()
+    nsCOMPtr<nsIScriptSecurityManager> securityManager = 
+      do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID, &rv);
+    if (securityManager) {
+      rv = securityManager->CheckLoadURI(parentBase, ourBase,
+                                         nsIScriptSecurityManager::STANDARD);
+    }
+  }
+  
+  if (NS_FAILED(rv)) {
+    NS_IF_ADDREF(*aBaseURL = parentBase);
+  } else {
+    NS_IF_ADDREF(*aBaseURL = ourBase);
+  }
+  
+  return NS_OK;    
 }
 
 NS_IMETHODIMP
diff --git a/mozilla/content/base/src/nsGenericElement.h b/mozilla/content/base/src/nsGenericElement.h
index 5c417c1bbab..0141ca03a4d 100644
--- a/mozilla/content/base/src/nsGenericElement.h
+++ b/mozilla/content/base/src/nsGenericElement.h
@@ -419,6 +419,7 @@ public:
   NS_IMETHOD SetBindingParent(nsIContent* aParent);
   NS_IMETHOD_(PRBool) IsContentOfType(PRUint32 aFlags);
   NS_IMETHOD GetListenerManager(nsIEventListenerManager** aInstancePtrResult);
+  NS_IMETHOD GetBaseURL(nsIURI** aBaseURL) const;
   NS_IMETHOD DoneCreatingElement();
 
 
@@ -433,7 +434,6 @@ public:
 
   // nsIXMLContent interface methods
   NS_IMETHOD MaybeTriggerAutoLink(nsIDocShell *aShell);
-  NS_IMETHOD GetXMLBaseURI(nsIURI **aURI);
 
   // nsIHTMLContent interface methods
   NS_IMETHOD Compact();
@@ -449,7 +449,6 @@ public:
   NS_IMETHOD StringToAttribute(nsIAtom* aAttribute,
                                const nsAString& aValue,
                                nsHTMLValue& aResult);
-  NS_IMETHOD GetBaseURL(nsIURI** aBaseURL) const;
   NS_IMETHOD GetBaseTarget(nsAString& aBaseTarget) const;
 
   // nsIDOMNode method implementation
diff --git a/mozilla/content/base/src/nsHTMLContentSerializer.cpp b/mozilla/content/base/src/nsHTMLContentSerializer.cpp
index e93157fc1ec..5c4d45fa57c 100644
--- a/mozilla/content/base/src/nsHTMLContentSerializer.cpp
+++ b/mozilla/content/base/src/nsHTMLContentSerializer.cpp
@@ -625,8 +625,6 @@ nsHTMLContentSerializer::SerializeAttributes(nsIContent* aContent,
         if (document) {
           nsCOMPtr<nsIURI> uri;
           document->GetBaseURL(getter_AddRefs(uri));
-          if (!uri)
-            document->GetDocumentURL(getter_AddRefs(uri));
           if (uri) {
             nsAutoString absURI;
             rv = NS_MakeAbsoluteURI(absURI, valueStr, uri);
diff --git a/mozilla/content/base/src/nsImageLoadingContent.cpp b/mozilla/content/base/src/nsImageLoadingContent.cpp
index 00f89a20fad..57b664ba5bf 100644
--- a/mozilla/content/base/src/nsImageLoadingContent.cpp
+++ b/mozilla/content/base/src/nsImageLoadingContent.cpp
@@ -383,7 +383,7 @@ nsImageLoadingContent::ImageURIChanged(const nsACString& aNewURI)
 
   nsresult rv;   // XXXbz Should failures in this method fire onerror?
 
-  // First, get a document (needed for security checks, base URI and the like)
+  // First, get a document (needed for security checks and the like)
   nsCOMPtr<nsIDocument> doc;
   rv = GetOurDocument(getter_AddRefs(doc));
   if (!doc) {
@@ -586,15 +586,9 @@ nsImageLoadingContent::StringToURI(const nsACString& aSpec,
   
   // (1) Get the base URI
   nsCOMPtr<nsIURI> baseURL;
-  nsCOMPtr<nsIHTMLContent> thisContent = do_QueryInterface(this);
-  if (thisContent) {
-    rv = thisContent->GetBaseURL(getter_AddRefs(baseURL));
-  } else {
-    rv = aDocument->GetBaseURL(getter_AddRefs(baseURL));
-    if (!baseURL) {
-      rv = aDocument->GetDocumentURL(getter_AddRefs(baseURL));
-    }
-  }
+  nsCOMPtr<nsIContent> thisContent = do_QueryInterface(this);
+  NS_ASSERTION(thisContent, "An image loading content must be an nsIContent");
+  rv = thisContent->GetBaseURL(getter_AddRefs(baseURL));
   NS_ENSURE_SUCCESS(rv, rv);
 
   // (2) Get the charset
diff --git a/mozilla/content/base/src/nsScriptLoader.cpp b/mozilla/content/base/src/nsScriptLoader.cpp
index 31dd50f4fb9..bfb05126675 100644
--- a/mozilla/content/base/src/nsScriptLoader.cpp
+++ b/mozilla/content/base/src/nsScriptLoader.cpp
@@ -401,7 +401,9 @@ nsScriptLoader::ProcessScriptElement(nsIDOMHTMLScriptElement *aElement,
     nsCOMPtr<nsIURI> baseURI, scriptURI;
     
     // Use the SRC attribute value to load the URL
-    mDocument->GetBaseURL(getter_AddRefs(baseURI));
+    nsCOMPtr<nsIContent> content(do_QueryInterface(aElement));
+    NS_ASSERTION(content, "nsIDOMHTMLScriptElement not implementing nsIContent");
+    content->GetBaseURL(getter_AddRefs(baseURI));
     rv = NS_NewURI(getter_AddRefs(scriptURI), src, nsnull, baseURI);
     if (NS_FAILED(rv)) {
       return FireErrorNotification(rv, aElement, aObserver);
diff --git a/mozilla/content/html/content/public/nsIHTMLContent.h b/mozilla/content/html/content/public/nsIHTMLContent.h
index 94041ab846a..977de13d308 100644
--- a/mozilla/content/html/content/public/nsIHTMLContent.h
+++ b/mozilla/content/html/content/public/nsIHTMLContent.h
@@ -133,16 +133,6 @@ public:
                                const nsAString& aValue,
                                nsHTMLValue& aResult) = 0;
 
-  /**
-   * Get the base URL for any relative URLs within this piece
-   * of content. Generally, this is the document's base URL,
-   * but certain content carries a local base for backward
-   * compatibility.
-   *
-   * @param aBaseURL the base URL [OUT]
-   */
-  NS_IMETHOD GetBaseURL(nsIURI** aBaseURL) const = 0;
-
   /**
    * Get the base target for any links within this piece
    * of content. Generally, this is the document's base target,
diff --git a/mozilla/content/html/content/src/nsAttributeContent.cpp b/mozilla/content/html/content/src/nsAttributeContent.cpp
index 698e778240e..d2771d4be96 100644
--- a/mozilla/content/html/content/src/nsAttributeContent.cpp
+++ b/mozilla/content/html/content/src/nsAttributeContent.cpp
@@ -64,7 +64,7 @@
 #include "nsVoidArray.h"
 #include "nsINameSpaceManager.h"
 #include "nsITextContent.h"
-
+#include "nsIURI.h"
 // XXX share all id's in this dir
 
 
@@ -135,6 +135,8 @@ public:
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
+  NS_IMETHOD GetBaseURL(nsIURI** aURI) const;
+  
   NS_IMETHOD DoneCreatingElement() {
     return NS_OK;
   }
@@ -373,6 +375,20 @@ nsAttributeContent::GetRangeList(nsVoidArray** aResult) const
   return NS_ERROR_FAILURE;
 }
 
+NS_IMETHODIMP
+nsAttributeContent::GetBaseURL(nsIURI** aURI) const
+{
+  if (mParent) {
+    return mParent->GetBaseURL(aURI);
+  }
+
+  if (mDocument) {
+    return mDocument->GetBaseURL(aURI);
+  }
+
+  *aURI = nsnull;
+  return NS_OK;
+}
 
 
 
diff --git a/mozilla/content/html/content/src/nsGenericHTMLElement.cpp b/mozilla/content/html/content/src/nsGenericHTMLElement.cpp
index 619c6cbb12e..d81b9fa8c6a 100644
--- a/mozilla/content/html/content/src/nsGenericHTMLElement.cpp
+++ b/mozilla/content/html/content/src/nsGenericHTMLElement.cpp
@@ -2355,18 +2355,36 @@ nsGenericHTMLElement::GetInlineStyleRule(nsIStyleRule** aStyleRule)
 nsresult
 nsGenericHTMLElement::GetBaseURL(nsIURI** aBaseURL) const
 {
-  nsHTMLValue baseHref;
-  if (mAttributes) {
-    mAttributes->GetAttribute(nsHTMLAtoms::_baseHref, baseHref);
-  }
-
   nsCOMPtr<nsIDocument> doc(mDocument);
 
   if (!doc) {
     mNodeInfo->GetDocument(getter_AddRefs(doc));
   }
 
-  return GetBaseURL(baseHref, doc, aBaseURL);
+  if (mAttributes &&
+      mAttributes->HasAttribute(nsHTMLAtoms::_baseHref, kNameSpaceID_None)) {
+
+    nsHTMLValue baseHref;
+    mAttributes->GetAttribute(nsHTMLAtoms::_baseHref, baseHref);
+
+    if (baseHref.GetUnit() == eHTMLUnit_String) {
+      // We have a _baseHref attribute; that will determine our base URL
+      return GetBaseURL(baseHref, doc, aBaseURL);
+    }
+  }
+
+  // If we are a plain old HTML element (not XHTML), don't bother asking the
+  // base class -- our base URL is determined solely by the document base.
+  if (mNodeInfo->NamespaceEquals(kNameSpaceID_None)) {
+    if (doc) {
+      return doc->GetBaseURL(aBaseURL);
+    }
+
+    *aBaseURL = nsnull;
+    return NS_OK;
+  }
+  
+  return nsGenericElement::GetBaseURL(aBaseURL);
 }
 
 nsresult
@@ -2385,7 +2403,6 @@ nsGenericHTMLElement::GetBaseURL(const nsHTMLValue& aBaseHref,
   if (eHTMLUnit_String == aBaseHref.GetUnit()) {
     nsAutoString baseHref;
     aBaseHref.GetStringValue(baseHref);
-    baseHref.Trim(" \t\n\r");
 
     *aBaseURL = nsnull;
     return NS_NewURI(aBaseURL, baseHref, nsnull, docBaseURL);
@@ -3101,7 +3118,7 @@ nsGenericHTMLElement::ParseStyleAttribute(const nsAString& aValue, nsHTMLValue&
   }
 
   if (doc) {
-    PRBool isCSS = PR_TRUE; // asume CSS until proven otherwise
+    PRBool isCSS = PR_TRUE; // assume CSS until proven otherwise
 
     nsAutoString styleType;
     doc->GetHeaderData(nsHTMLAtoms::headerContentStyleType, styleType);
@@ -3130,11 +3147,12 @@ nsGenericHTMLElement::ParseStyleAttribute(const nsAString& aValue, nsHTMLValue&
         }
       }
       if (cssParser) {
-        nsCOMPtr<nsIURI> docURL;
-        doc->GetBaseURL(getter_AddRefs(docURL));
+        nsCOMPtr<nsIURI> baseURL;
+        GetBaseURL(getter_AddRefs(baseURL));
 
         nsCOMPtr<nsIStyleRule> rule;
-        result = cssParser->ParseStyleAttribute(aValue, docURL, getter_AddRefs(rule));
+        result = cssParser->ParseStyleAttribute(aValue, baseURL,
+                                                getter_AddRefs(rule));
         if (cssLoader) {
           cssLoader->RecycleParser(cssParser);
         }
@@ -3429,6 +3447,8 @@ nsGenericHTMLElement::MapBackgroundAttributesInto(const nsIHTMLMappedAttributes*
         value.GetStringValue(spec);
         if (!spec.IsEmpty()) {
           // Resolve url to an absolute url
+          // XXX this breaks if the HTML element has an xml:base
+          // attribute (the xml:base will not be taken into account)
           nsCOMPtr<nsIPresShell> shell;
           nsresult rv = aData->mPresContext->GetShell(getter_AddRefs(shell));
           if (NS_SUCCEEDED(rv) && shell) {
@@ -4604,10 +4624,6 @@ nsGenericHTMLElement::GetProtocolFromHrefString(const nsAString& aHref,
 
     if (aDocument) {
       aDocument->GetBaseURL(getter_AddRefs(uri));
-
-      if (!uri) {
-        aDocument->GetDocumentURL(getter_AddRefs(uri));
-      }
     }
 
     if (uri) {
@@ -4615,7 +4631,7 @@ nsGenericHTMLElement::GetProtocolFromHrefString(const nsAString& aHref,
     }
 
     if (protocol.IsEmpty()) {
-      // set the protocol to http since it is the mostlikely protocol
+      // set the protocol to http since it is the most likely protocol
       // to be used.
 
       CopyASCIItoUCS2(nsDependentCString("http:"), aProtocol);
diff --git a/mozilla/content/html/style/src/nsCSSLoader.cpp b/mozilla/content/html/style/src/nsCSSLoader.cpp
index 20451f63202..c6268a4badc 100644
--- a/mozilla/content/html/style/src/nsCSSLoader.cpp
+++ b/mozilla/content/html/style/src/nsCSSLoader.cpp
@@ -956,6 +956,7 @@ CSSLoaderImpl::CheckLoadAllowed(nsIURI* aSourceURI,
  */
 nsresult
 CSSLoaderImpl::CreateSheet(nsIURI* aURI,
+                           nsIContent* aLinkingContent,
                            PRUint32 aDefaultNameSpaceID,
                            PRBool aSyncLoad,
                            StyleSheetState& aSheetState,
@@ -1039,8 +1040,8 @@ CSSLoaderImpl::CreateSheet(nsIURI* aURI,
     if (!sheetURI) {
       // Inline style.  Use the document's base URL so that @import in
       // the inline sheet picks up the right base.
-      NS_ASSERTION(mDocument, "How did we get in here without a document?");
-      mDocument->GetBaseURL(getter_AddRefs(sheetURI));
+      NS_ASSERTION(aLinkingContent, "Inline stylesheet without linking content?");
+      aLinkingContent->GetBaseURL(getter_AddRefs(sheetURI));
     }
 
     rv = NS_NewCSSStyleSheet(aSheet, sheetURI);
@@ -1094,7 +1095,7 @@ CSSLoaderImpl::PrepareSheet(nsICSSStyleSheet* aSheet,
  */
 nsresult
 CSSLoaderImpl::InsertSheetInDoc(nsICSSStyleSheet* aSheet,
-                                nsIContent* aLinkingElement,
+                                nsIContent* aLinkingContent,
                                 nsIDocument* aDocument)
 {
   LOG(("CSSLoaderImpl::InsertSheetInDoc"));
@@ -1103,8 +1104,8 @@ CSSLoaderImpl::InsertSheetInDoc(nsICSSStyleSheet* aSheet,
 
   // all nodes that link in sheets should be implementing nsIDOM3Node
   nsresult rv = NS_OK;
-  nsCOMPtr<nsIDOM3Node> linkingNode = do_QueryInterface(aLinkingElement);
-  NS_ASSERTION(linkingNode || !aLinkingElement,
+  nsCOMPtr<nsIDOM3Node> linkingNode = do_QueryInterface(aLinkingContent);
+  NS_ASSERTION(linkingNode || !aLinkingContent,
                "Need to implement nsIDOM3Node to get insertion order right");
 
   // XXX Need to cancel pending sheet loads for this element, if any
@@ -1168,7 +1169,7 @@ CSSLoaderImpl::InsertSheetInDoc(nsICSSStyleSheet* aSheet,
   // XXX <meta> elements do not implement nsIStyleSheetLinkingElement;
   // need to fix this for them to be ordered correctly.
   nsCOMPtr<nsIStyleSheetLinkingElement>
-    linkingElement = do_QueryInterface(aLinkingElement);
+    linkingElement = do_QueryInterface(aLinkingContent);
   if (linkingElement) {
     linkingElement->SetStyleSheet(aSheet); // This sets the ownerNode on the sheet
   }
@@ -1589,8 +1590,8 @@ CSSLoaderImpl::LoadInlineStyle(nsIContent* aElement,
   
   StyleSheetState state;
   nsCOMPtr<nsICSSStyleSheet> sheet;
-  nsresult rv = CreateSheet(nsnull, aDefaultNameSpaceID, PR_FALSE, state,
-                            getter_AddRefs(sheet));
+  nsresult rv = CreateSheet(nsnull, aElement, aDefaultNameSpaceID, PR_FALSE,
+                            state, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
   NS_ASSERTION(state == eSheetNeedsParser,
                "Inline sheets should not be cached");
@@ -1651,7 +1652,7 @@ CSSLoaderImpl::LoadStyleLink(nsIContent* aElement,
   
   StyleSheetState state;
   nsCOMPtr<nsICSSStyleSheet> sheet;
-  rv = CreateSheet(aURL, aDefaultNameSpaceID, PR_FALSE, state,
+  rv = CreateSheet(aURL, aElement, aDefaultNameSpaceID, PR_FALSE, state,
                    getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
 
@@ -1761,7 +1762,7 @@ CSSLoaderImpl::LoadChildSheet(nsICSSStyleSheet* aParentSheet,
   // loop) do so
   nsCOMPtr<nsICSSStyleSheet> sheet;
   StyleSheetState state;
-  rv = CreateSheet(aURL, aDefaultNameSpaceID,
+  rv = CreateSheet(aURL, nsnull, aDefaultNameSpaceID,
                    parentData ? parentData->mSyncLoad : PR_FALSE,
                    state, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
@@ -1833,8 +1834,8 @@ CSSLoaderImpl::InternalLoadAgentSheet(nsIURI* aURL,
   nsCOMPtr<nsICSSStyleSheet> sheet;
   PRBool syncLoad = (aObserver == nsnull);
   
-  nsresult rv = CreateSheet(aURL, kNameSpaceID_Unknown, syncLoad, state,
-                            getter_AddRefs(sheet));
+  nsresult rv = CreateSheet(aURL, nsnull, kNameSpaceID_Unknown, syncLoad,
+                            state, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
 
   NS_NAMED_LITERAL_STRING(empty, "");
diff --git a/mozilla/content/html/style/src/nsCSSLoader.h b/mozilla/content/html/style/src/nsCSSLoader.h
index e99e3f16b61..5b72b77a352 100644
--- a/mozilla/content/html/style/src/nsCSSLoader.h
+++ b/mozilla/content/html/style/src/nsCSSLoader.h
@@ -307,8 +307,11 @@ private:
   nsresult CheckLoadAllowed(nsIURI* aSourceURI,
                             nsIURI* aTargetURI,
                             nsISupports* aContext);
-  
+
+  // For inline style, the aURI param is null, but the aLinkingContent
+  // must be non-null then.
   nsresult CreateSheet(nsIURI* aURI,
+                       nsIContent* aLinkingContent,
                        PRUint32 aDefaultNameSpaceID,
                        PRBool aSyncLoad,
                        StyleSheetState& aSheetState,
@@ -319,7 +322,7 @@ private:
                         const nsAString& aMedia);
 
   nsresult InsertSheetInDoc(nsICSSStyleSheet* aSheet,
-                            nsIContent* aLinkingElement,
+                            nsIContent* aLinkingContent,
                             nsIDocument* aDocument);
 
   nsresult InsertChildSheet(nsICSSStyleSheet* aSheet,
diff --git a/mozilla/content/html/style/src/nsDOMCSSAttrDeclaration.cpp b/mozilla/content/html/style/src/nsDOMCSSAttrDeclaration.cpp
index dd1e79d1b9d..e4130536955 100644
--- a/mozilla/content/html/style/src/nsDOMCSSAttrDeclaration.cpp
+++ b/mozilla/content/html/style/src/nsDOMCSSAttrDeclaration.cpp
@@ -168,15 +168,15 @@ nsDOMCSSAttributeDeclaration::GetCSSParsingEnvironment(nsIURI** aBaseURI,
   if (NS_FAILED(result)) {
     return result;
   }
+
+  mContent->GetBaseURL(aBaseURI);
   
-  if (doc) {
-    doc->GetBaseURL(aBaseURI);
-    nsCOMPtr<nsIHTMLContentContainer> htmlContainer(do_QueryInterface(doc));
-    if (htmlContainer) {
-      htmlContainer->GetCSSLoader(*aCSSLoader);
-    }
-    NS_ASSERTION(*aCSSLoader, "Document with no CSS loader!");
+  nsCOMPtr<nsIHTMLContentContainer> htmlContainer(do_QueryInterface(doc));
+  if (htmlContainer) {
+    htmlContainer->GetCSSLoader(*aCSSLoader);
   }
+  NS_ASSERTION(!doc || *aCSSLoader, "Document with no CSS loader!");
+  
   if (*aCSSLoader) {
     result = (*aCSSLoader)->GetParserFor(nsnull, aCSSParser);
   } else {
diff --git a/mozilla/content/html/style/src/nsStyleUtil.cpp b/mozilla/content/html/style/src/nsStyleUtil.cpp
index 7def156cbfc..f59f2170320 100644
--- a/mozilla/content/html/style/src/nsStyleUtil.cpp
+++ b/mozilla/content/html/style/src/nsStyleUtil.cpp
@@ -647,22 +647,9 @@ PRBool nsStyleUtil::IsSimpleXlink(nsIContent *aContent, nsIPresContext *aPresCon
         // is it bad to re-use val here?
         aContent->GetAttr(kNameSpaceID_XLink, nsHTMLAtoms::href, val);
 
-        // It's an XLink. Resolve it relative to its document.
+        // It's an XLink. Resolve it relative to aContent's base URI.
         nsCOMPtr<nsIURI> baseURI;
-        nsCOMPtr<nsIHTMLContent> htmlContent = do_QueryInterface(aContent);
-        if (htmlContent) {
-          // XXX why do this? will nsIHTMLContent's
-          // GetBaseURL() may return something different
-          // than the URL of the document it lives in?
-          htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-        }
-        else {
-          nsCOMPtr<nsIDocument> doc;
-          aContent->GetDocument(getter_AddRefs(doc));
-          if (doc) {
-            doc->GetBaseURL(getter_AddRefs(baseURI));
-          }
-        }
+        aContent->GetBaseURL(getter_AddRefs(baseURI));
 
         nsCOMPtr<nsIURI> absURI;
         // XXX should we make sure to get the right charset off the document?
diff --git a/mozilla/content/svg/content/src/nsISVGStyleValue.h b/mozilla/content/svg/content/src/nsISVGStyleValue.h
index 0f19150bc4a..7aff7bba8a6 100644
--- a/mozilla/content/svg/content/src/nsISVGStyleValue.h
+++ b/mozilla/content/svg/content/src/nsISVGStyleValue.h
@@ -43,7 +43,7 @@
 #include "nsISupports.h"
 
 class nsIStyleRule;
-class nsIDocument;
+class nsIContent;
 
 // {BD099C4C-8FA5-47c4-A44E-189B5AA5DBAF}
 #define NS_ISVGSTYLEVALUE_IID \
@@ -54,7 +54,7 @@ class nsISVGStyleValue : public nsISupports
 public:
   NS_DEFINE_STATIC_IID_ACCESSOR(NS_ISVGSTYLEVALUE_IID)
   
-  NS_IMETHOD GetStyleRule(nsIDocument* baseDocument, nsIStyleRule** rule)=0;
+  NS_IMETHOD GetStyleRule(nsIContent* aContent, nsIStyleRule** rule)=0;
 };
 
 #endif // __NS_ISVGSTYLEVALUE_H__
diff --git a/mozilla/content/svg/content/src/nsSVGElement.cpp b/mozilla/content/svg/content/src/nsSVGElement.cpp
index 0936926575e..3ca0604c861 100644
--- a/mozilla/content/svg/content/src/nsSVGElement.cpp
+++ b/mozilla/content/svg/content/src/nsSVGElement.cpp
@@ -447,7 +447,7 @@ nsSVGElement::WalkContentStyleRules(nsRuleWalker* aRuleWalker)
 NS_IMETHODIMP
 nsSVGElement::GetInlineStyleRule(nsIStyleRule** aStyleRule)
 {
-  return mStyle->GetStyleRule(mDocument, aStyleRule);
+  return mStyle->GetStyleRule(this, aStyleRule);
 }
 
 NS_IMETHODIMP
diff --git a/mozilla/content/svg/content/src/nsSVGStyleValue.cpp b/mozilla/content/svg/content/src/nsSVGStyleValue.cpp
index d1a8cbffed1..e5d1a9c9d36 100644
--- a/mozilla/content/svg/content/src/nsSVGStyleValue.cpp
+++ b/mozilla/content/svg/content/src/nsSVGStyleValue.cpp
@@ -40,7 +40,7 @@
 #include "nsISVGStyleValue.h"
 #include "nsSVGStyleValue.h"
 #include "nsIStyleRule.h"
-#include "nsIDocument.h"
+#include "nsIContent.h"
 #include "nsIURI.h"
 #include "nsICSSParser.h"
 #include "nsIServiceManager.h"
@@ -65,11 +65,11 @@ public:
   NS_IMETHOD GetValueString(nsAString& aValue);
 
   // nsISVGStyleValue interface:
-  NS_IMETHOD GetStyleRule(nsIDocument* baseDoc, nsIStyleRule** rule);
+  NS_IMETHOD GetStyleRule(nsIContent* aContent, nsIStyleRule** rule);
   
 protected:
   // Implementation helpers:
-  void UpdateStyleRule(nsIDocument* baseDoc);
+  void UpdateStyleRule(nsIContent* aContent);
   
   nsString mValue;
   nsCOMPtr<nsIStyleRule> mRule; // lazily cached
@@ -127,10 +127,10 @@ nsSVGStyleValue::GetValueString(nsAString& aValue)
 // nsISVGStyleValue interface:
 
 NS_IMETHODIMP
-nsSVGStyleValue::GetStyleRule(nsIDocument* baseDoc, nsIStyleRule** rule)
+nsSVGStyleValue::GetStyleRule(nsIContent* aContent, nsIStyleRule** rule)
 {
   if (!mRule) {
-    UpdateStyleRule(baseDoc);
+    UpdateStyleRule(aContent);
   }
   
   *rule = mRule;
@@ -143,7 +143,7 @@ nsSVGStyleValue::GetStyleRule(nsIDocument* baseDoc, nsIStyleRule** rule)
 // Implementation helpers:
 
 void
-nsSVGStyleValue::UpdateStyleRule(nsIDocument* baseDoc)
+nsSVGStyleValue::UpdateStyleRule(nsIContent* aContent)
 {
   
   if (mValue.IsEmpty()) {
@@ -152,17 +152,13 @@ nsSVGStyleValue::UpdateStyleRule(nsIDocument* baseDoc)
     return;
   }
 
-  NS_ASSERTION(baseDoc,"need base document");
-  nsCOMPtr <nsIURI> docURL;
-  baseDoc->GetBaseURL(getter_AddRefs(docURL));
+  NS_ASSERTION(aContent, "need content node for base URL");
+  nsCOMPtr <nsIURI> baseURL;
+  aContent->GetBaseURL(getter_AddRefs(baseURL));
   
-  nsCOMPtr<nsICSSParser> css;
-  nsComponentManager::CreateInstance(kCSSParserCID,
-                                     nsnull,
-                                     NS_GET_IID(nsICSSParser),
-                                     getter_AddRefs(css));
+  nsCOMPtr<nsICSSParser> css = do_CreateInstance(kCSSParserCID);
   NS_ASSERTION(css, "can't get a css parser");
   if (!css) return;    
 
-  css->ParseStyleAttribute(mValue, docURL, getter_AddRefs(mRule)); 
+  css->ParseStyleAttribute(mValue, baseURL, getter_AddRefs(mRule)); 
 }
diff --git a/mozilla/content/xml/content/public/nsIXMLContent.h b/mozilla/content/xml/content/public/nsIXMLContent.h
index f76e0efae98..ddd8162078f 100644
--- a/mozilla/content/xml/content/public/nsIXMLContent.h
+++ b/mozilla/content/xml/content/public/nsIXMLContent.h
@@ -75,12 +75,6 @@ public:
    *         which case, the caller should stop parsing as well.
    */
   NS_IMETHOD MaybeTriggerAutoLink(nsIDocShell *aShell) = 0;
-
-  /**
-   * Get the XML Base URI for this element (http://www.w3.org/TR/xmlbase/)
-   * @param aURI the base URI [OUT]
-   */
-  NS_IMETHOD GetXMLBaseURI(nsIURI **aURI) = 0;
 };
 
 nsresult
diff --git a/mozilla/content/xml/content/src/nsXMLElement.cpp b/mozilla/content/xml/content/src/nsXMLElement.cpp
index c970b8c31a6..c60dc494171 100644
--- a/mozilla/content/xml/content/src/nsXMLElement.cpp
+++ b/mozilla/content/xml/content/src/nsXMLElement.cpp
@@ -147,125 +147,6 @@ NS_IMPL_ADDREF_INHERITED(nsXMLElement, nsGenericElement)
 NS_IMPL_RELEASE_INHERITED(nsXMLElement, nsGenericElement)
 
 
-NS_IMETHODIMP
-nsXMLElement::GetXMLBaseURI(nsIURI **aURI)
-{
-  NS_ENSURE_ARG_POINTER(aURI);
-  *aURI = nsnull;
-  
-  nsresult rv;
-
-  nsAutoString base;
-  nsCOMPtr<nsIContent> content(do_QueryInterface(NS_STATIC_CAST(nsIXMLContent*,this),&rv));
-  while (NS_SUCCEEDED(rv) && content) {
-    nsAutoString value;
-    rv = content->GetAttr(kNameSpaceID_XML,nsHTMLAtoms::base,value);
-    PRInt32 value_len;
-    if (rv == NS_CONTENT_ATTR_HAS_VALUE) {
-      PRInt32 colon = value.FindChar(':');
-      PRInt32 slash = value.FindChar('/');
-      if (colon > 0 && !( slash >= 0 && slash < colon)) {
-        // Yay, we have absolute path!
-        // The complex looking if above is to make sure that we do not erroneously
-        // think a value of "./this:that" would have a scheme of "./that"
-
-        rv = NS_NewURIWithDocumentCharset(aURI, value, mDocument, nsnull);
-        if (NS_FAILED(rv))
-          break;
-
-        if (!base.IsEmpty()) { // XXXdarin base is always empty
-          NS_ConvertUTF16toUTF8 str(base);
-          nsCAutoString resolvedStr;
-          rv = (*aURI)->Resolve(str, resolvedStr);
-          if (NS_FAILED(rv)) break;
-          rv = (*aURI)->SetSpec(resolvedStr);
-        }
-        break;
-
-      } else if ((value_len = value.Length()) > 0) {        
-        if (!base.IsEmpty()) {
-          if (base[0] == '/') {
-            // Do nothing, we are waiting for a scheme starting value
-          } else {
-            // We do not want to add double / delimiters (although the user is free to do so)
-            if (value[value_len - 1] != '/')
-              value.Append(PRUnichar('/'));
-            base.Insert(value, 0);
-          }
-        } else {
-          if (value[value_len - 1] != '/')
-            value.Append(PRUnichar('/')); // Add delimiter/make sure we treat this as dir
-          base = value;
-        }
-      }
-    } // if (rv == NS_CONTENT_ATTR_HAS_VALUE) {
-    nsCOMPtr<nsIContent> parent;
-    rv = content->GetParent(getter_AddRefs(parent));
-    content = parent;
-  } // while
-
-  if (NS_SUCCEEDED(rv)) {
-    if (!*aURI && mDocument) {
-      nsCOMPtr<nsIURI> docBase;
-      mDocument->GetBaseURL(getter_AddRefs(docBase));
-      if (!docBase) {
-        mDocument->GetDocumentURL(getter_AddRefs(docBase));
-      }
-      if (base.IsEmpty()) {
-        *aURI = docBase.get();    
-        NS_IF_ADDREF(*aURI);  // nsCOMPtr releases this once
-      } else {
-        rv = NS_NewURIWithDocumentCharset(aURI, base, mDocument, docBase);
-      }
-    }
-
-    // Finally do a security check, almost the same as nsDocument::SetBaseURL()
-    if (*aURI) {
-      nsCOMPtr<nsIScriptSecurityManager> securityManager = 
-        do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID, &rv);
-      if (NS_SUCCEEDED(rv)) {
-        nsCOMPtr<nsIURI> docURI;
-        mDocument->GetDocumentURL(getter_AddRefs(docURI));
-        rv = securityManager->CheckLoadURI(docURI, *aURI, nsIScriptSecurityManager::STANDARD);
-        if (NS_FAILED(rv)) {
-          // Now we need to get the "closest" allowed base URI
-          NS_RELEASE(*aURI);
-
-          if (content) { // content is the last content we tried above
-            nsCOMPtr<nsIContent> parent;
-            content->GetParent(getter_AddRefs(parent));
-            content = parent;
-            while (content) {
-              nsCOMPtr<nsIXMLContent> xml(do_QueryInterface(content));
-              if (xml) {
-                return xml->GetXMLBaseURI(aURI);
-              }
-              content->GetParent(getter_AddRefs(parent));
-              content = parent;
-            }
-          }
-          
-          nsCOMPtr<nsIURI> docBase;
-          mDocument->GetBaseURL(getter_AddRefs(docBase));
-          if (!docBase) {
-            mDocument->GetDocumentURL(getter_AddRefs(docBase));
-          }
-
-          *aURI = docBase.get();
-          NS_IF_ADDREF(*aURI);
-          rv = NS_OK;
-        }
-      }
-    }
-  }
-
-  if (NS_FAILED(rv)) {
-    NS_IF_RELEASE(*aURI);
-  }
-
-  return rv;
-}
-
 NS_IMETHODIMP
 nsXMLElement::SetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
                       const nsAString& aValue,
@@ -309,7 +190,6 @@ static nsresult DocShellToPresContext(nsIDocShell *aShell,
   return ds->GetPresContext(aPresContext);
 }
 
-
 static nsresult CheckLoadURI(const nsString& aSpec, nsIURI *aBaseURI,
                              nsIDocument* aDocument, nsIURI **aAbsURI)
 {
@@ -428,7 +308,7 @@ nsXMLElement::MaybeTriggerAutoLink(nsIDocShell *aShell)
 
         // base
         nsCOMPtr<nsIURI> base;
-        rv = GetXMLBaseURI(getter_AddRefs(base));
+        rv = GetBaseURL(getter_AddRefs(base));
         if (NS_FAILED(rv))
           break;
 
@@ -528,7 +408,7 @@ nsXMLElement::HandleDOMEvent(nsIPresContext* aPresContext,
           }
 
           nsCOMPtr<nsIURI> baseURL;
-          GetXMLBaseURI(getter_AddRefs(baseURL));
+          GetBaseURL(getter_AddRefs(baseURL));
           nsCOMPtr<nsIURI> uri;
           ret = NS_NewURIWithDocumentCharset(getter_AddRefs(uri), href,
                                              mDocument, baseURL);
@@ -587,7 +467,7 @@ nsXMLElement::HandleDOMEvent(nsIPresContext* aPresContext,
         }
 
         nsCOMPtr<nsIURI> baseURL;
-        GetXMLBaseURI(getter_AddRefs(baseURL));
+        GetBaseURL(getter_AddRefs(baseURL));
 
         nsCOMPtr<nsIURI> uri;
         ret = NS_NewURIWithDocumentCharset(getter_AddRefs(uri), href,
diff --git a/mozilla/content/xml/content/src/nsXMLElement.h b/mozilla/content/xml/content/src/nsXMLElement.h
index 4be91205b30..b4319e80b28 100644
--- a/mozilla/content/xml/content/src/nsXMLElement.h
+++ b/mozilla/content/xml/content/src/nsXMLElement.h
@@ -69,7 +69,6 @@ public:
 
   // nsIXMLContent
   NS_IMETHOD MaybeTriggerAutoLink(nsIDocShell *aShell);
-  NS_IMETHOD GetXMLBaseURI(nsIURI **aURI);
 
   // nsIStyledContent
   NS_IMETHOD GetID(nsIAtom** aResult) const;
diff --git a/mozilla/content/xul/content/src/nsXULElement.cpp b/mozilla/content/xul/content/src/nsXULElement.cpp
index 4ecbf7e71ec..03993412a21 100644
--- a/mozilla/content/xul/content/src/nsXULElement.cpp
+++ b/mozilla/content/xul/content/src/nsXULElement.cpp
@@ -1591,38 +1591,6 @@ nsXULElement::MaybeTriggerAutoLink(nsIDocShell *aShell)
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsXULElement::GetXMLBaseURI(nsIURI **aURI)
-{
-  // XXX TODO, should share the impl with nsXMLElement
-  NS_ENSURE_ARG_POINTER(aURI);
-  *aURI = nsnull;
-  if (mDocument) {
-    mDocument->GetBaseURL(aURI);
-    if (!*aURI) {
-      mDocument->GetDocumentURL(aURI);
-    }
-  }
-  return NS_OK;
-}
-
-#if 0
-NS_IMETHODIMP
-nsXULElement::GetBaseURI(nsAString &aURI)
-{
-  // XXX TODO, should share the impl with nsXMLElement
-  aURI.Truncate();
-  nsresult rv = NS_OK;
-  if (mDocument) {
-    nsCOMPtr<nsIDOMDocument> doc(do_QueryInterface(mDocument));
-    if (doc) {
-      rv = doc->GetBaseURI(aURI);
-    }
-  }
-  return rv;
-}
-#endif
-
 //----------------------------------------------------------------------
 // nsIXULContent interface
 
@@ -2472,12 +2440,10 @@ nsXULElement::SetAttr(nsINodeInfo* aNodeInfo,
     // Check to see if the STYLE attribute is being set.  If so, we need to
     // create a new style rule based off the value of this attribute, and we
     // need to let the document know about the StyleRule change.
-    // XXXbz this should not be checking for mDocument; it should get
-    // the document off the nodeinfo
-    if (aNodeInfo->Equals(nsXULAtoms::style, kNameSpaceID_None) && mDocument) {
-        nsCOMPtr <nsIURI> docURL;
-        mDocument->GetBaseURL(getter_AddRefs(docURL));
-        Attributes()->UpdateStyleRule(docURL, aValue);
+    if (aNodeInfo->Equals(nsXULAtoms::style, kNameSpaceID_None)) {
+        nsCOMPtr <nsIURI> baseURL;
+        GetBaseURL(getter_AddRefs(baseURL));
+        Attributes()->UpdateStyleRule(baseURL, aValue);
     }
 
     nsCOMPtr<nsIAtom> tag;
@@ -2750,17 +2716,15 @@ nsXULElement::UnsetAttr(PRInt32 aNameSpaceID,
     // XXXwaterson if aNotify == PR_TRUE, do we want to call
     // nsIDocument::BeginUpdate() now?
     if (aNameSpaceID == kNameSpaceID_None) {
-      if (mDocument) {
         if (aName == nsXULAtoms::clazz) {
             // If CLASS is being unset, delete our class list.
             Attributes()->UpdateClassList(nsAutoString());
         } else if (aName == nsXULAtoms::style) {
-            nsCOMPtr <nsIURI> docURL;
-            mDocument->GetBaseURL(getter_AddRefs(docURL));
-            Attributes()->UpdateStyleRule(docURL, nsAutoString());
+            nsCOMPtr <nsIURI> baseURL;
+            GetBaseURL(getter_AddRefs(baseURL));
+            Attributes()->UpdateStyleRule(baseURL, nsAutoString());
             // XXX Some kind of special document update might need to happen here.
         }
-      }
     }
 
     nsCOMPtr<nsIAtom> tag;
@@ -3383,6 +3347,18 @@ nsXULElement::SetContentID(PRUint32 aID)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsXULElement::GetBaseURL(nsIURI **aURI) const
+{
+  // XXX TODO, should share the impl with nsGenericElement
+  if (mDocument) {
+    return mDocument->GetBaseURL(aURI);
+  }
+
+  *aURI = nsnull;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsXULElement::RangeAdd(nsIDOMRange* aRange)
 {
diff --git a/mozilla/content/xul/content/src/nsXULElement.h b/mozilla/content/xul/content/src/nsXULElement.h
index f3528b861ef..fbf2ccf1bbc 100644
--- a/mozilla/content/xul/content/src/nsXULElement.h
+++ b/mozilla/content/xul/content/src/nsXULElement.h
@@ -459,11 +459,11 @@ public:
     NS_IMETHOD GetBindingParent(nsIContent** aContent);
     NS_IMETHOD SetBindingParent(nsIContent* aParent);
     NS_IMETHOD_(PRBool) IsContentOfType(PRUint32 aFlags);
+    NS_IMETHOD GetBaseURL(nsIURI** aURI) const;
     NS_IMETHOD GetListenerManager(nsIEventListenerManager** aResult);
 
     // nsIXMLContent
     NS_IMETHOD MaybeTriggerAutoLink(nsIDocShell *aShell);
-    NS_IMETHOD GetXMLBaseURI(nsIURI **aURI);
 
     // nsIStyledContent
     NS_IMETHOD GetID(nsIAtom** aResult) const;
diff --git a/mozilla/dom/src/base/nsLocation.cpp b/mozilla/dom/src/base/nsLocation.cpp
index 1f9d26f02ee..35f4d4c07d9 100644
--- a/mozilla/dom/src/base/nsLocation.cpp
+++ b/mozilla/dom/src/base/nsLocation.cpp
@@ -930,14 +930,10 @@ LocationImpl::GetSourceBaseURL(JSContext* cx, nsIURI** sourceURL)
   nsCOMPtr<nsIDocument> doc;
   nsresult rv = GetSourceDocument(cx, getter_AddRefs(doc));
   if (doc) {
-    rv = doc->GetBaseURL(sourceURL);
-
-    if (!*sourceURL) {
-      doc->GetDocumentURL(sourceURL);
-    }
-  } else {
-    *sourceURL = nsnull;
+    return doc->GetBaseURL(sourceURL);
   }
+
+  *sourceURL = nsnull;
   return rv;
 }
 
diff --git a/mozilla/editor/libeditor/html/nsHTMLEditor.cpp b/mozilla/editor/libeditor/html/nsHTMLEditor.cpp
index ae21db0381a..b36b7b3ab7d 100644
--- a/mozilla/editor/libeditor/html/nsHTMLEditor.cpp
+++ b/mozilla/editor/libeditor/html/nsHTMLEditor.cpp
@@ -5982,23 +5982,24 @@ nsHTMLEditor::ParseStyleAttrIntoCSSRule(const nsAString& aString,
     return NS_ERROR_UNEXPECTED;
   nsCOMPtr <nsIURI> docURL;
   doc->GetBaseURL(getter_AddRefs(docURL));
-  nsCOMPtr<nsICSSParser> css;
-  nsCOMPtr<nsIStyleRule> mRule;
-  nsComponentManager::CreateInstance(kCSSParserCID,
-                                     nsnull,
-                                     NS_GET_IID(nsICSSParser),
-                                     getter_AddRefs(css));
+  nsCOMPtr<nsICSSParser> css = do_CreateInstance(kCSSParserCID);;
   NS_ASSERTION(css, "can't get a css parser");
   if (!css) return NS_ERROR_NULL_POINTER;    
 
-  //nsAutoString value(aString);
+  nsCOMPtr<nsIStyleRule> mRule;
   css->ParseStyleAttribute(aString, docURL, getter_AddRefs(mRule));
-  nsCOMPtr<nsIDOMCSSStyleRule> styleRule = do_QueryInterface(mRule);
-  if (styleRule) {
-    *_retval = styleRule;
-    NS_ADDREF(*_retval);
+  nsCOMPtr<nsICSSRule> styleRule = do_QueryInterface(mRule);
+  if (!styleRule) {
+    return NS_ERROR_UNEXPECTED;
   }
-  return NS_OK;
+
+  nsCOMPtr<nsIDOMCSSRule> domRule;
+  styleRule->GetDOMRule(getter_AddRefs(domRule));
+  if (!domRule) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  
+  return CallQueryInterface(domRule, _retval);
 }
 
 NS_IMETHODIMP
diff --git a/mozilla/embedding/components/windowwatcher/src/nsWindowWatcher.cpp b/mozilla/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
index 298a4ed3800..ad930cfc899 100644
--- a/mozilla/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
+++ b/mozilla/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
@@ -1140,10 +1140,6 @@ nsWindowWatcher::URIfromURL(const char *aURL,
       doc = do_QueryInterface(domDoc);
       if (doc) {
         doc->GetBaseURL(getter_AddRefs(baseURI));
-
-        if (!baseURI) {
-          doc->GetDocumentURL(getter_AddRefs(baseURI));
-        }
       }
     }
   }
diff --git a/mozilla/layout/generic/nsBulletFrame.cpp b/mozilla/layout/generic/nsBulletFrame.cpp
index 5078cf57457..f5d9ceb071c 100644
--- a/mozilla/layout/generic/nsBulletFrame.cpp
+++ b/mozilla/layout/generic/nsBulletFrame.cpp
@@ -135,7 +135,7 @@ nsBulletFrame::Init(nsIPresContext*  aPresContext,
     GetLoadGroup(aPresContext, getter_AddRefs(loadGroup));
 
     nsCOMPtr<nsIURI> baseURI;
-    GetBaseURI(getter_AddRefs(baseURI));
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
 
     nsCOMPtr<nsIURI> imgURI;
     NS_NewURI(getter_AddRefs(imgURI), myList->mListStyleImage, nsnull, baseURI);
@@ -1597,7 +1597,7 @@ nsBulletFrame::Reflow(nsIPresContext* aPresContext,
 
   if (isStyleChange) {
     nsCOMPtr<nsIURI> baseURI;
-    GetBaseURI(getter_AddRefs(baseURI));
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
 
     const nsStyleList* myList = GetStyleList();
 
@@ -1811,30 +1811,6 @@ NS_IMETHODIMP nsBulletFrame::FrameChanged(imgIContainer *aContainer,
   return NS_OK;
 }
 
-
-
-void
-nsBulletFrame::GetBaseURI(nsIURI **aURI)
-{
-  NS_PRECONDITION(nsnull != aURI, "null OUT parameter pointer");
-
-  nsresult rv;
-  nsCOMPtr<nsIURI> baseURI;
-  nsCOMPtr<nsIHTMLContent> htmlContent(do_QueryInterface(mContent, &rv));
-  if (NS_SUCCEEDED(rv)) {
-    htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-  }
-  else {
-    nsCOMPtr<nsIDocument> doc;
-    mContent->GetDocument(getter_AddRefs(doc));
-    if (doc) {
-      doc->GetBaseURL(getter_AddRefs(baseURI));
-    }
-  }
-  *aURI = baseURI;
-  NS_IF_ADDREF(*aURI);
-}
-
 void
 nsBulletFrame::GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup)
 {
diff --git a/mozilla/layout/generic/nsBulletFrame.h b/mozilla/layout/generic/nsBulletFrame.h
index 5347797db4f..cd3b44e073e 100644
--- a/mozilla/layout/generic/nsBulletFrame.h
+++ b/mozilla/layout/generic/nsBulletFrame.h
@@ -100,7 +100,6 @@ protected:
                          const nsStyleList& aStyleList,
                          nsString& aResult);
 
-  void GetBaseURI(nsIURI **aURI);
   void GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup);
 
   PRInt32 mOrdinal;
diff --git a/mozilla/layout/generic/nsImageFrame.cpp b/mozilla/layout/generic/nsImageFrame.cpp
index 7517ed96c08..ee2b13df38f 100644
--- a/mozilla/layout/generic/nsImageFrame.cpp
+++ b/mozilla/layout/generic/nsImageFrame.cpp
@@ -1692,7 +1692,7 @@ nsImageFrame::HandleEvent(nsIPresContext* aPresContext,
 
         if (!inside && isServerMap) {
           nsCOMPtr<nsIURI> baseURL;
-          GetBaseURI(getter_AddRefs(baseURL));
+          mContent->GetBaseURL(getter_AddRefs(baseURL));
           
           if (baseURL) {
             // Server side image maps use the href in a containing anchor
@@ -1906,7 +1906,9 @@ nsImageFrame::SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
                          nsIURI **aURI)
 {
   nsCOMPtr<nsIURI> baseURI;
-  GetBaseURI(getter_AddRefs(baseURI));
+  if (mContent) {
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
+  }
   nsCAutoString charset;
   GetDocumentCharacterSet(charset);
   NS_NewURI(aURI, aSpec, 
@@ -1914,30 +1916,6 @@ nsImageFrame::SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
             baseURI, aIOService);
 }
 
-void
-nsImageFrame::GetBaseURI(nsIURI **aURI)
-{
-  NS_PRECONDITION(nsnull != aURI, "null OUT parameter pointer");
-
-  nsresult rv;
-  nsCOMPtr<nsIURI> baseURI;
-  nsCOMPtr<nsIHTMLContent> htmlContent(do_QueryInterface(mContent, &rv));
-  if (NS_SUCCEEDED(rv)) {
-    htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-  }
-  else {
-    nsCOMPtr<nsIDocument> doc;
-    if (mContent) {
-      rv = mContent->GetDocument(getter_AddRefs(doc));
-      if (doc) {
-        doc->GetBaseURL(getter_AddRefs(baseURI));
-      }
-    }
-  }
-  *aURI = baseURI;
-  NS_IF_ADDREF(*aURI);
-}
-
 void
 nsImageFrame::GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup)
 {
diff --git a/mozilla/layout/generic/nsImageFrame.h b/mozilla/layout/generic/nsImageFrame.h
index 0113a1438ee..065f32a2c95 100644
--- a/mozilla/layout/generic/nsImageFrame.h
+++ b/mozilla/layout/generic/nsImageFrame.h
@@ -200,7 +200,6 @@ private:
   inline void SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
                         nsIURI **aURI);
 
-  inline void GetBaseURI(nsIURI **uri);
   inline void GetLoadGroup(nsIPresContext *aPresContext,
                            nsILoadGroup **aLoadGroup);
   nscoord GetContinuationOffset(nscoord* aWidth = 0) const;
diff --git a/mozilla/layout/generic/nsObjectFrame.cpp b/mozilla/layout/generic/nsObjectFrame.cpp
index bcc779e27bd..4c3cc60ee8a 100644
--- a/mozilla/layout/generic/nsObjectFrame.cpp
+++ b/mozilla/layout/generic/nsObjectFrame.cpp
@@ -560,7 +560,7 @@ void nsObjectFrame::IsSupportedDocument(nsIContent* aContent, PRBool* aDoc)
     nsCOMPtr<nsIURI> uri;
     nsCOMPtr<nsIURI> baseURL;
 
-    if (NS_FAILED(GetBaseURL(*getter_AddRefs(baseURL)))) return; // XXX NS_NewURI fails without base
+    aContent->GetBaseURL(getter_AddRefs(baseURL));
     rv = NS_NewURI(getter_AddRefs(uri), data, nsnull, baseURL);
     if (NS_FAILED(rv)) return;
 
@@ -1022,16 +1022,15 @@ nsObjectFrame::Reflow(nsIPresContext*          aPresContext,
 
     nsAutoString classid;
 
-    if (NS_SUCCEEDED(rv = GetBaseURL(*getter_AddRefs(baseURL)))) {
-      nsAutoString codeBase;
-      if ((NS_CONTENT_ATTR_HAS_VALUE ==
-            mContent->GetAttr(kNameSpaceID_None, nsHTMLAtoms::codebase, codeBase)) &&
-          !codeBase.IsEmpty()) {
-        nsCOMPtr<nsIURI> codeBaseURL;
-        rv = MakeAbsoluteURL(getter_AddRefs(codeBaseURL), codeBase, baseURL);
-        if (NS_SUCCEEDED(rv)) {
-          baseURL = codeBaseURL;
-        }
+    mContent->GetBaseURL(getter_AddRefs(baseURL));
+    nsAutoString codeBase;
+    if ((NS_CONTENT_ATTR_HAS_VALUE ==
+         mContent->GetAttr(kNameSpaceID_None, nsHTMLAtoms::codebase, codeBase)) &&
+        !codeBase.IsEmpty()) {
+      nsCOMPtr<nsIURI> codeBaseURL;
+      rv = MakeAbsoluteURL(getter_AddRefs(codeBaseURL), codeBase, baseURL);
+      if (NS_SUCCEEDED(rv)) {
+        baseURL = codeBaseURL;
       }
     }
 
@@ -1392,29 +1391,6 @@ nsObjectFrame::HandleChild(nsIPresContext*          aPresContext,
   return NS_OK;
 }
 
-
-nsresult
-nsObjectFrame::GetBaseURL(nsIURI* &aURL)
-{
-  nsIHTMLContent* htmlContent;
-  if (NS_SUCCEEDED(mContent->QueryInterface(NS_GET_IID(nsIHTMLContent), (void**)&htmlContent))) 
-  {
-    htmlContent->GetBaseURL(&aURL);
-    NS_RELEASE(htmlContent);
-  }
-  else 
-  {
-    nsCOMPtr<nsIDocument> doc;
-    mContent->GetDocument(getter_AddRefs(doc));
-    if (doc)
-      doc->GetBaseURL(&aURL);
-    else
-      return NS_ERROR_FAILURE;
-  }
-  return NS_OK;
-}
-
-
 PRBool
 nsObjectFrame::IsHidden(PRBool aCheckVisibilityStyle) const
 {
@@ -2289,6 +2265,8 @@ NS_IMETHODIMP nsPluginInstanceOwner::GetURL(const char *aURL, const char *aTarge
   nsCOMPtr<nsIDocument> doc;
   rv = GetDocument(getter_AddRefs(doc));
   if (NS_SUCCEEDED(rv) && doc) {
+    // XXX should this really be the document base URL?  Or the
+    // content's base URL?
     rv = doc->GetBaseURL(getter_AddRefs(baseURL));  // gets the document's url
   } else {
     mOwner->GetFullURL(*getter_AddRefs(baseURL)); // gets the plugin's content url
@@ -2846,13 +2824,11 @@ void nsObjectFrame::FixUpURLS(const nsString &name, nsString &value)
       name.EqualsIgnoreCase("PLUGINSPAGE")) {        
     
     nsCOMPtr<nsIURI> baseURL;
-    GetBaseURL(*getter_AddRefs(baseURL));
-    if (baseURL) {
-      nsAutoString newURL;
-      NS_MakeAbsoluteURI(newURL, value, baseURL);
-      if (!newURL.IsEmpty())
-        value = newURL;
-    }
+    mContent->GetBaseURL(getter_AddRefs(baseURL));
+    nsAutoString newURL;
+    NS_MakeAbsoluteURI(newURL, value, baseURL);
+    if (!newURL.IsEmpty())
+      value = newURL;
   }
 }
 
diff --git a/mozilla/layout/generic/nsObjectFrame.h b/mozilla/layout/generic/nsObjectFrame.h
index 3e89c4b7bfe..5b94072c9b1 100644
--- a/mozilla/layout/generic/nsObjectFrame.h
+++ b/mozilla/layout/generic/nsObjectFrame.h
@@ -171,8 +171,6 @@ protected:
                        nsReflowStatus&          aStatus,
                        nsIFrame*                child);
  
-  nsresult GetBaseURL(nsIURI* &aURL);
-
   // check attributes and optionally CSS to see if we should display anything
   PRBool IsHidden(PRBool aCheckVisibilityStyle = PR_TRUE) const;
 
diff --git a/mozilla/layout/html/base/src/nsBulletFrame.cpp b/mozilla/layout/html/base/src/nsBulletFrame.cpp
index 5078cf57457..f5d9ceb071c 100644
--- a/mozilla/layout/html/base/src/nsBulletFrame.cpp
+++ b/mozilla/layout/html/base/src/nsBulletFrame.cpp
@@ -135,7 +135,7 @@ nsBulletFrame::Init(nsIPresContext*  aPresContext,
     GetLoadGroup(aPresContext, getter_AddRefs(loadGroup));
 
     nsCOMPtr<nsIURI> baseURI;
-    GetBaseURI(getter_AddRefs(baseURI));
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
 
     nsCOMPtr<nsIURI> imgURI;
     NS_NewURI(getter_AddRefs(imgURI), myList->mListStyleImage, nsnull, baseURI);
@@ -1597,7 +1597,7 @@ nsBulletFrame::Reflow(nsIPresContext* aPresContext,
 
   if (isStyleChange) {
     nsCOMPtr<nsIURI> baseURI;
-    GetBaseURI(getter_AddRefs(baseURI));
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
 
     const nsStyleList* myList = GetStyleList();
 
@@ -1811,30 +1811,6 @@ NS_IMETHODIMP nsBulletFrame::FrameChanged(imgIContainer *aContainer,
   return NS_OK;
 }
 
-
-
-void
-nsBulletFrame::GetBaseURI(nsIURI **aURI)
-{
-  NS_PRECONDITION(nsnull != aURI, "null OUT parameter pointer");
-
-  nsresult rv;
-  nsCOMPtr<nsIURI> baseURI;
-  nsCOMPtr<nsIHTMLContent> htmlContent(do_QueryInterface(mContent, &rv));
-  if (NS_SUCCEEDED(rv)) {
-    htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-  }
-  else {
-    nsCOMPtr<nsIDocument> doc;
-    mContent->GetDocument(getter_AddRefs(doc));
-    if (doc) {
-      doc->GetBaseURL(getter_AddRefs(baseURI));
-    }
-  }
-  *aURI = baseURI;
-  NS_IF_ADDREF(*aURI);
-}
-
 void
 nsBulletFrame::GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup)
 {
diff --git a/mozilla/layout/html/base/src/nsBulletFrame.h b/mozilla/layout/html/base/src/nsBulletFrame.h
index 5347797db4f..cd3b44e073e 100644
--- a/mozilla/layout/html/base/src/nsBulletFrame.h
+++ b/mozilla/layout/html/base/src/nsBulletFrame.h
@@ -100,7 +100,6 @@ protected:
                          const nsStyleList& aStyleList,
                          nsString& aResult);
 
-  void GetBaseURI(nsIURI **aURI);
   void GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup);
 
   PRInt32 mOrdinal;
diff --git a/mozilla/layout/html/base/src/nsImageFrame.cpp b/mozilla/layout/html/base/src/nsImageFrame.cpp
index 7517ed96c08..ee2b13df38f 100644
--- a/mozilla/layout/html/base/src/nsImageFrame.cpp
+++ b/mozilla/layout/html/base/src/nsImageFrame.cpp
@@ -1692,7 +1692,7 @@ nsImageFrame::HandleEvent(nsIPresContext* aPresContext,
 
         if (!inside && isServerMap) {
           nsCOMPtr<nsIURI> baseURL;
-          GetBaseURI(getter_AddRefs(baseURL));
+          mContent->GetBaseURL(getter_AddRefs(baseURL));
           
           if (baseURL) {
             // Server side image maps use the href in a containing anchor
@@ -1906,7 +1906,9 @@ nsImageFrame::SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
                          nsIURI **aURI)
 {
   nsCOMPtr<nsIURI> baseURI;
-  GetBaseURI(getter_AddRefs(baseURI));
+  if (mContent) {
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
+  }
   nsCAutoString charset;
   GetDocumentCharacterSet(charset);
   NS_NewURI(aURI, aSpec, 
@@ -1914,30 +1916,6 @@ nsImageFrame::SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
             baseURI, aIOService);
 }
 
-void
-nsImageFrame::GetBaseURI(nsIURI **aURI)
-{
-  NS_PRECONDITION(nsnull != aURI, "null OUT parameter pointer");
-
-  nsresult rv;
-  nsCOMPtr<nsIURI> baseURI;
-  nsCOMPtr<nsIHTMLContent> htmlContent(do_QueryInterface(mContent, &rv));
-  if (NS_SUCCEEDED(rv)) {
-    htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-  }
-  else {
-    nsCOMPtr<nsIDocument> doc;
-    if (mContent) {
-      rv = mContent->GetDocument(getter_AddRefs(doc));
-      if (doc) {
-        doc->GetBaseURL(getter_AddRefs(baseURI));
-      }
-    }
-  }
-  *aURI = baseURI;
-  NS_IF_ADDREF(*aURI);
-}
-
 void
 nsImageFrame::GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup)
 {
diff --git a/mozilla/layout/html/base/src/nsImageFrame.h b/mozilla/layout/html/base/src/nsImageFrame.h
index 0113a1438ee..065f32a2c95 100644
--- a/mozilla/layout/html/base/src/nsImageFrame.h
+++ b/mozilla/layout/html/base/src/nsImageFrame.h
@@ -200,7 +200,6 @@ private:
   inline void SpecToURI(const nsAString& aSpec, nsIIOService *aIOService,
                         nsIURI **aURI);
 
-  inline void GetBaseURI(nsIURI **uri);
   inline void GetLoadGroup(nsIPresContext *aPresContext,
                            nsILoadGroup **aLoadGroup);
   nscoord GetContinuationOffset(nscoord* aWidth = 0) const;
diff --git a/mozilla/layout/html/base/src/nsObjectFrame.cpp b/mozilla/layout/html/base/src/nsObjectFrame.cpp
index bcc779e27bd..4c3cc60ee8a 100644
--- a/mozilla/layout/html/base/src/nsObjectFrame.cpp
+++ b/mozilla/layout/html/base/src/nsObjectFrame.cpp
@@ -560,7 +560,7 @@ void nsObjectFrame::IsSupportedDocument(nsIContent* aContent, PRBool* aDoc)
     nsCOMPtr<nsIURI> uri;
     nsCOMPtr<nsIURI> baseURL;
 
-    if (NS_FAILED(GetBaseURL(*getter_AddRefs(baseURL)))) return; // XXX NS_NewURI fails without base
+    aContent->GetBaseURL(getter_AddRefs(baseURL));
     rv = NS_NewURI(getter_AddRefs(uri), data, nsnull, baseURL);
     if (NS_FAILED(rv)) return;
 
@@ -1022,16 +1022,15 @@ nsObjectFrame::Reflow(nsIPresContext*          aPresContext,
 
     nsAutoString classid;
 
-    if (NS_SUCCEEDED(rv = GetBaseURL(*getter_AddRefs(baseURL)))) {
-      nsAutoString codeBase;
-      if ((NS_CONTENT_ATTR_HAS_VALUE ==
-            mContent->GetAttr(kNameSpaceID_None, nsHTMLAtoms::codebase, codeBase)) &&
-          !codeBase.IsEmpty()) {
-        nsCOMPtr<nsIURI> codeBaseURL;
-        rv = MakeAbsoluteURL(getter_AddRefs(codeBaseURL), codeBase, baseURL);
-        if (NS_SUCCEEDED(rv)) {
-          baseURL = codeBaseURL;
-        }
+    mContent->GetBaseURL(getter_AddRefs(baseURL));
+    nsAutoString codeBase;
+    if ((NS_CONTENT_ATTR_HAS_VALUE ==
+         mContent->GetAttr(kNameSpaceID_None, nsHTMLAtoms::codebase, codeBase)) &&
+        !codeBase.IsEmpty()) {
+      nsCOMPtr<nsIURI> codeBaseURL;
+      rv = MakeAbsoluteURL(getter_AddRefs(codeBaseURL), codeBase, baseURL);
+      if (NS_SUCCEEDED(rv)) {
+        baseURL = codeBaseURL;
       }
     }
 
@@ -1392,29 +1391,6 @@ nsObjectFrame::HandleChild(nsIPresContext*          aPresContext,
   return NS_OK;
 }
 
-
-nsresult
-nsObjectFrame::GetBaseURL(nsIURI* &aURL)
-{
-  nsIHTMLContent* htmlContent;
-  if (NS_SUCCEEDED(mContent->QueryInterface(NS_GET_IID(nsIHTMLContent), (void**)&htmlContent))) 
-  {
-    htmlContent->GetBaseURL(&aURL);
-    NS_RELEASE(htmlContent);
-  }
-  else 
-  {
-    nsCOMPtr<nsIDocument> doc;
-    mContent->GetDocument(getter_AddRefs(doc));
-    if (doc)
-      doc->GetBaseURL(&aURL);
-    else
-      return NS_ERROR_FAILURE;
-  }
-  return NS_OK;
-}
-
-
 PRBool
 nsObjectFrame::IsHidden(PRBool aCheckVisibilityStyle) const
 {
@@ -2289,6 +2265,8 @@ NS_IMETHODIMP nsPluginInstanceOwner::GetURL(const char *aURL, const char *aTarge
   nsCOMPtr<nsIDocument> doc;
   rv = GetDocument(getter_AddRefs(doc));
   if (NS_SUCCEEDED(rv) && doc) {
+    // XXX should this really be the document base URL?  Or the
+    // content's base URL?
     rv = doc->GetBaseURL(getter_AddRefs(baseURL));  // gets the document's url
   } else {
     mOwner->GetFullURL(*getter_AddRefs(baseURL)); // gets the plugin's content url
@@ -2846,13 +2824,11 @@ void nsObjectFrame::FixUpURLS(const nsString &name, nsString &value)
       name.EqualsIgnoreCase("PLUGINSPAGE")) {        
     
     nsCOMPtr<nsIURI> baseURL;
-    GetBaseURL(*getter_AddRefs(baseURL));
-    if (baseURL) {
-      nsAutoString newURL;
-      NS_MakeAbsoluteURI(newURL, value, baseURL);
-      if (!newURL.IsEmpty())
-        value = newURL;
-    }
+    mContent->GetBaseURL(getter_AddRefs(baseURL));
+    nsAutoString newURL;
+    NS_MakeAbsoluteURI(newURL, value, baseURL);
+    if (!newURL.IsEmpty())
+      value = newURL;
   }
 }
 
diff --git a/mozilla/layout/html/base/src/nsObjectFrame.h b/mozilla/layout/html/base/src/nsObjectFrame.h
index 3e89c4b7bfe..5b94072c9b1 100644
--- a/mozilla/layout/html/base/src/nsObjectFrame.h
+++ b/mozilla/layout/html/base/src/nsObjectFrame.h
@@ -171,8 +171,6 @@ protected:
                        nsReflowStatus&          aStatus,
                        nsIFrame*                child);
  
-  nsresult GetBaseURL(nsIURI* &aURL);
-
   // check attributes and optionally CSS to see if we should display anything
   PRBool IsHidden(PRBool aCheckVisibilityStyle = PR_TRUE) const;
 
diff --git a/mozilla/layout/style/nsCSSLoader.cpp b/mozilla/layout/style/nsCSSLoader.cpp
index 20451f63202..c6268a4badc 100644
--- a/mozilla/layout/style/nsCSSLoader.cpp
+++ b/mozilla/layout/style/nsCSSLoader.cpp
@@ -956,6 +956,7 @@ CSSLoaderImpl::CheckLoadAllowed(nsIURI* aSourceURI,
  */
 nsresult
 CSSLoaderImpl::CreateSheet(nsIURI* aURI,
+                           nsIContent* aLinkingContent,
                            PRUint32 aDefaultNameSpaceID,
                            PRBool aSyncLoad,
                            StyleSheetState& aSheetState,
@@ -1039,8 +1040,8 @@ CSSLoaderImpl::CreateSheet(nsIURI* aURI,
     if (!sheetURI) {
       // Inline style.  Use the document's base URL so that @import in
       // the inline sheet picks up the right base.
-      NS_ASSERTION(mDocument, "How did we get in here without a document?");
-      mDocument->GetBaseURL(getter_AddRefs(sheetURI));
+      NS_ASSERTION(aLinkingContent, "Inline stylesheet without linking content?");
+      aLinkingContent->GetBaseURL(getter_AddRefs(sheetURI));
     }
 
     rv = NS_NewCSSStyleSheet(aSheet, sheetURI);
@@ -1094,7 +1095,7 @@ CSSLoaderImpl::PrepareSheet(nsICSSStyleSheet* aSheet,
  */
 nsresult
 CSSLoaderImpl::InsertSheetInDoc(nsICSSStyleSheet* aSheet,
-                                nsIContent* aLinkingElement,
+                                nsIContent* aLinkingContent,
                                 nsIDocument* aDocument)
 {
   LOG(("CSSLoaderImpl::InsertSheetInDoc"));
@@ -1103,8 +1104,8 @@ CSSLoaderImpl::InsertSheetInDoc(nsICSSStyleSheet* aSheet,
 
   // all nodes that link in sheets should be implementing nsIDOM3Node
   nsresult rv = NS_OK;
-  nsCOMPtr<nsIDOM3Node> linkingNode = do_QueryInterface(aLinkingElement);
-  NS_ASSERTION(linkingNode || !aLinkingElement,
+  nsCOMPtr<nsIDOM3Node> linkingNode = do_QueryInterface(aLinkingContent);
+  NS_ASSERTION(linkingNode || !aLinkingContent,
                "Need to implement nsIDOM3Node to get insertion order right");
 
   // XXX Need to cancel pending sheet loads for this element, if any
@@ -1168,7 +1169,7 @@ CSSLoaderImpl::InsertSheetInDoc(nsICSSStyleSheet* aSheet,
   // XXX <meta> elements do not implement nsIStyleSheetLinkingElement;
   // need to fix this for them to be ordered correctly.
   nsCOMPtr<nsIStyleSheetLinkingElement>
-    linkingElement = do_QueryInterface(aLinkingElement);
+    linkingElement = do_QueryInterface(aLinkingContent);
   if (linkingElement) {
     linkingElement->SetStyleSheet(aSheet); // This sets the ownerNode on the sheet
   }
@@ -1589,8 +1590,8 @@ CSSLoaderImpl::LoadInlineStyle(nsIContent* aElement,
   
   StyleSheetState state;
   nsCOMPtr<nsICSSStyleSheet> sheet;
-  nsresult rv = CreateSheet(nsnull, aDefaultNameSpaceID, PR_FALSE, state,
-                            getter_AddRefs(sheet));
+  nsresult rv = CreateSheet(nsnull, aElement, aDefaultNameSpaceID, PR_FALSE,
+                            state, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
   NS_ASSERTION(state == eSheetNeedsParser,
                "Inline sheets should not be cached");
@@ -1651,7 +1652,7 @@ CSSLoaderImpl::LoadStyleLink(nsIContent* aElement,
   
   StyleSheetState state;
   nsCOMPtr<nsICSSStyleSheet> sheet;
-  rv = CreateSheet(aURL, aDefaultNameSpaceID, PR_FALSE, state,
+  rv = CreateSheet(aURL, aElement, aDefaultNameSpaceID, PR_FALSE, state,
                    getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
 
@@ -1761,7 +1762,7 @@ CSSLoaderImpl::LoadChildSheet(nsICSSStyleSheet* aParentSheet,
   // loop) do so
   nsCOMPtr<nsICSSStyleSheet> sheet;
   StyleSheetState state;
-  rv = CreateSheet(aURL, aDefaultNameSpaceID,
+  rv = CreateSheet(aURL, nsnull, aDefaultNameSpaceID,
                    parentData ? parentData->mSyncLoad : PR_FALSE,
                    state, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
@@ -1833,8 +1834,8 @@ CSSLoaderImpl::InternalLoadAgentSheet(nsIURI* aURL,
   nsCOMPtr<nsICSSStyleSheet> sheet;
   PRBool syncLoad = (aObserver == nsnull);
   
-  nsresult rv = CreateSheet(aURL, kNameSpaceID_Unknown, syncLoad, state,
-                            getter_AddRefs(sheet));
+  nsresult rv = CreateSheet(aURL, nsnull, kNameSpaceID_Unknown, syncLoad,
+                            state, getter_AddRefs(sheet));
   NS_ENSURE_SUCCESS(rv, rv);
 
   NS_NAMED_LITERAL_STRING(empty, "");
diff --git a/mozilla/layout/style/nsCSSLoader.h b/mozilla/layout/style/nsCSSLoader.h
index e99e3f16b61..5b72b77a352 100644
--- a/mozilla/layout/style/nsCSSLoader.h
+++ b/mozilla/layout/style/nsCSSLoader.h
@@ -307,8 +307,11 @@ private:
   nsresult CheckLoadAllowed(nsIURI* aSourceURI,
                             nsIURI* aTargetURI,
                             nsISupports* aContext);
-  
+
+  // For inline style, the aURI param is null, but the aLinkingContent
+  // must be non-null then.
   nsresult CreateSheet(nsIURI* aURI,
+                       nsIContent* aLinkingContent,
                        PRUint32 aDefaultNameSpaceID,
                        PRBool aSyncLoad,
                        StyleSheetState& aSheetState,
@@ -319,7 +322,7 @@ private:
                         const nsAString& aMedia);
 
   nsresult InsertSheetInDoc(nsICSSStyleSheet* aSheet,
-                            nsIContent* aLinkingElement,
+                            nsIContent* aLinkingContent,
                             nsIDocument* aDocument);
 
   nsresult InsertChildSheet(nsICSSStyleSheet* aSheet,
diff --git a/mozilla/layout/style/nsDOMCSSAttrDeclaration.cpp b/mozilla/layout/style/nsDOMCSSAttrDeclaration.cpp
index dd1e79d1b9d..e4130536955 100644
--- a/mozilla/layout/style/nsDOMCSSAttrDeclaration.cpp
+++ b/mozilla/layout/style/nsDOMCSSAttrDeclaration.cpp
@@ -168,15 +168,15 @@ nsDOMCSSAttributeDeclaration::GetCSSParsingEnvironment(nsIURI** aBaseURI,
   if (NS_FAILED(result)) {
     return result;
   }
+
+  mContent->GetBaseURL(aBaseURI);
   
-  if (doc) {
-    doc->GetBaseURL(aBaseURI);
-    nsCOMPtr<nsIHTMLContentContainer> htmlContainer(do_QueryInterface(doc));
-    if (htmlContainer) {
-      htmlContainer->GetCSSLoader(*aCSSLoader);
-    }
-    NS_ASSERTION(*aCSSLoader, "Document with no CSS loader!");
+  nsCOMPtr<nsIHTMLContentContainer> htmlContainer(do_QueryInterface(doc));
+  if (htmlContainer) {
+    htmlContainer->GetCSSLoader(*aCSSLoader);
   }
+  NS_ASSERTION(!doc || *aCSSLoader, "Document with no CSS loader!");
+  
   if (*aCSSLoader) {
     result = (*aCSSLoader)->GetParserFor(nsnull, aCSSParser);
   } else {
diff --git a/mozilla/layout/style/nsStyleUtil.cpp b/mozilla/layout/style/nsStyleUtil.cpp
index 7def156cbfc..f59f2170320 100644
--- a/mozilla/layout/style/nsStyleUtil.cpp
+++ b/mozilla/layout/style/nsStyleUtil.cpp
@@ -647,22 +647,9 @@ PRBool nsStyleUtil::IsSimpleXlink(nsIContent *aContent, nsIPresContext *aPresCon
         // is it bad to re-use val here?
         aContent->GetAttr(kNameSpaceID_XLink, nsHTMLAtoms::href, val);
 
-        // It's an XLink. Resolve it relative to its document.
+        // It's an XLink. Resolve it relative to aContent's base URI.
         nsCOMPtr<nsIURI> baseURI;
-        nsCOMPtr<nsIHTMLContent> htmlContent = do_QueryInterface(aContent);
-        if (htmlContent) {
-          // XXX why do this? will nsIHTMLContent's
-          // GetBaseURL() may return something different
-          // than the URL of the document it lives in?
-          htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-        }
-        else {
-          nsCOMPtr<nsIDocument> doc;
-          aContent->GetDocument(getter_AddRefs(doc));
-          if (doc) {
-            doc->GetBaseURL(getter_AddRefs(baseURI));
-          }
-        }
+        aContent->GetBaseURL(getter_AddRefs(baseURI));
 
         nsCOMPtr<nsIURI> absURI;
         // XXX should we make sure to get the right charset off the document?
diff --git a/mozilla/layout/xul/base/src/nsImageBoxFrame.cpp b/mozilla/layout/xul/base/src/nsImageBoxFrame.cpp
index e9a7ddb7b8b..72e38fe8378 100644
--- a/mozilla/layout/xul/base/src/nsImageBoxFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsImageBoxFrame.cpp
@@ -431,7 +431,9 @@ nsImageBoxFrame::UpdateImage(nsIPresContext*  aPresContext, PRBool& aResize)
   }
 
   nsCOMPtr<nsIURI> baseURI;
-  GetBaseURI(getter_AddRefs(baseURI));
+  if (mContent) {
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
+  }
   nsCOMPtr<nsIURI> srcURI;
   nsresult rv = NS_NewURI(getter_AddRefs(srcURI), mSrc, nsnull, baseURI);
 
@@ -710,26 +712,6 @@ nsImageBoxFrame::GetFrameName(nsAString& aResult) const
 #endif
 
 
-void
-nsImageBoxFrame::GetBaseURI(nsIURI **uri)
-{
-  nsresult rv;
-  nsCOMPtr<nsIURI> baseURI;
-  nsCOMPtr<nsIHTMLContent> htmlContent(do_QueryInterface(mContent, &rv));
-  if (NS_SUCCEEDED(rv)) {
-    htmlContent->GetBaseURL(getter_AddRefs(baseURI));
-  }
-  else {
-    nsCOMPtr<nsIDocument> doc;
-    mContent->GetDocument(getter_AddRefs(doc));
-    if (doc) {
-      doc->GetBaseURL(getter_AddRefs(baseURI));
-    }
-  }
-  *uri = baseURI;
-  NS_IF_ADDREF(*uri);
-}
-
 void
 nsImageBoxFrame::GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **aLoadGroup)
 {
diff --git a/mozilla/layout/xul/base/src/nsImageBoxFrame.h b/mozilla/layout/xul/base/src/nsImageBoxFrame.h
index beca5a9b1ba..3c5edb50697 100644
--- a/mozilla/layout/xul/base/src/nsImageBoxFrame.h
+++ b/mozilla/layout/xul/base/src/nsImageBoxFrame.h
@@ -138,8 +138,6 @@ protected:
 
   void GetImageSource();
 
-  void GetBaseURI(nsIURI **uri);
-
   void GetLoadGroup(nsIPresContext *aPresContext, nsILoadGroup **group);
 
   virtual void GetImageSize(nsIPresContext* aPresContext);
diff --git a/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp b/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
index 49e635d1366..534b2aa9ff4 100644
--- a/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
+++ b/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
@@ -1944,7 +1944,8 @@ nsTreeBodyFrame::GetImage(PRInt32 aRowIndex, const PRUnichar* aColID, PRBool aUs
     if (!doc)
       // The page is currently being torn down.  Why bother.
       return NS_ERROR_FAILURE;
-    doc->GetBaseURL(getter_AddRefs(baseURI));
+
+    mContent->GetBaseURL(getter_AddRefs(baseURI));
 
     nsCOMPtr<nsIURI> srcURI;
     NS_NewURI(getter_AddRefs(srcURI), *imagePtr, nsnull, baseURI);