diff --git a/mozilla/content/base/public/nsIStyleSheetLinkingElement.h b/mozilla/content/base/public/nsIStyleSheetLinkingElement.h
index ee78986cab4..3ac13ba22af 100644
--- a/mozilla/content/base/public/nsIStyleSheetLinkingElement.h
+++ b/mozilla/content/base/public/nsIStyleSheetLinkingElement.h
@@ -90,9 +90,11 @@ public:
    *                     from one document to another).
    * @param aObserver    observer to notify once the stylesheet is loaded.
    *                     It might be notified before the function returns.
+   * @param aForceUpdate If true, force the update even if the URI did not change
    */
   NS_IMETHOD UpdateStyleSheet(nsIDocument *aOldDocument,
-                              nsICSSLoaderObserver* aObserver) = 0;
+                              nsICSSLoaderObserver* aObserver,
+                              PRBool aForceUpdate = PR_FALSE) = 0;
 
   /**
    * Tells this element whether to update the stylesheet when the
diff --git a/mozilla/content/base/src/nsStyleLinkElement.cpp b/mozilla/content/base/src/nsStyleLinkElement.cpp
index 4d0f52b38f6..e2faf551f68 100644
--- a/mozilla/content/base/src/nsStyleLinkElement.cpp
+++ b/mozilla/content/base/src/nsStyleLinkElement.cpp
@@ -189,7 +189,8 @@ const PRBool kBlockByDefault=PR_TRUE;
 
 NS_IMETHODIMP
 nsStyleLinkElement::UpdateStyleSheet(nsIDocument *aOldDocument,
-                                     nsICSSLoaderObserver* aObserver)
+                                     nsICSSLoaderObserver* aObserver,
+                                     PRBool aForceUpdate)
 {
   if (mStyleSheet && aOldDocument) {
     // We're removing the link element from the document, unload the
@@ -228,7 +229,7 @@ nsStyleLinkElement::UpdateStyleSheet(nsIDocument *aOldDocument,
   PRBool isInline;
   GetStyleSheetURL(&isInline, getter_AddRefs(uri));
 
-  if (mStyleSheet && !isInline && uri) {
+  if (!aForceUpdate && mStyleSheet && !isInline && uri) {
     nsCOMPtr<nsIURI> oldURI;
 
     mStyleSheet->GetSheetURI(getter_AddRefs(oldURI));
diff --git a/mozilla/content/base/src/nsStyleLinkElement.h b/mozilla/content/base/src/nsStyleLinkElement.h
index f8aa93a7baa..d46d40e4e71 100644
--- a/mozilla/content/base/src/nsStyleLinkElement.h
+++ b/mozilla/content/base/src/nsStyleLinkElement.h
@@ -64,8 +64,12 @@ public:
   NS_IMETHOD SetStyleSheet(nsIStyleSheet* aStyleSheet);
   NS_IMETHOD GetStyleSheet(nsIStyleSheet*& aStyleSheet);
   NS_IMETHOD InitStyleLinkElement(nsIParser *aParser, PRBool aDontLoadStyle);
+  // If aForceUpdate == PR_TRUE will force the update even if the URI has not
+  // changed.  This should be used in cases when something about the content
+  // that affects the resulting sheet changed but the URI may not have changed.
   NS_IMETHOD UpdateStyleSheet(nsIDocument *aOldDocument = nsnull,
-                              nsICSSLoaderObserver* aObserver = nsnull);
+                              nsICSSLoaderObserver* aObserver = nsnull,
+                              PRBool aForceUpdate = PR_FALSE);
   NS_IMETHOD SetEnableUpdates(PRBool aEnableUpdates);
   NS_IMETHOD GetCharset(nsAString& aCharset);
   virtual void SetLineNumber(PRUint32 aLineNumber);
diff --git a/mozilla/content/html/content/src/nsHTMLLinkElement.cpp b/mozilla/content/html/content/src/nsHTMLLinkElement.cpp
index 90298906c1c..8ab0685f6cc 100644
--- a/mozilla/content/html/content/src/nsHTMLLinkElement.cpp
+++ b/mozilla/content/html/content/src/nsHTMLLinkElement.cpp
@@ -295,7 +295,12 @@ nsHTMLLinkElement::SetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
   nsresult rv = nsGenericHTMLElement::SetAttr(aNameSpaceID, aName, aPrefix,
                                               aValue, aNotify);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull,
+                     aNameSpaceID == kNameSpaceID_None &&
+                     (aName == nsHTMLAtoms::rel ||
+                      aName == nsHTMLAtoms::title ||
+                      aName == nsHTMLAtoms::media ||
+                      aName == nsHTMLAtoms::type));
   }
 
   return rv;
@@ -308,7 +313,12 @@ nsHTMLLinkElement::UnsetAttr(PRInt32 aNameSpaceID, nsIAtom* aAttribute,
   nsresult rv = nsGenericHTMLElement::UnsetAttr(aNameSpaceID, aAttribute,
                                                 aNotify);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull,
+                     aNameSpaceID == kNameSpaceID_None &&
+                     (aAttribute == nsHTMLAtoms::rel ||
+                      aAttribute == nsHTMLAtoms::title ||
+                      aAttribute == nsHTMLAtoms::media ||
+                      aAttribute == nsHTMLAtoms::type));
   }
 
   return rv;
diff --git a/mozilla/content/html/content/src/nsHTMLStyleElement.cpp b/mozilla/content/html/content/src/nsHTMLStyleElement.cpp
index 1ed5682d4c3..0caa76d7576 100644
--- a/mozilla/content/html/content/src/nsHTMLStyleElement.cpp
+++ b/mozilla/content/html/content/src/nsHTMLStyleElement.cpp
@@ -240,7 +240,11 @@ nsHTMLStyleElement::SetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
   nsresult rv = nsGenericHTMLElement::SetAttr(aNameSpaceID, aName, aPrefix,
                                               aValue, aNotify);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull,
+                     aNameSpaceID == kNameSpaceID_None &&
+                     (aName == nsHTMLAtoms::title ||
+                      aName == nsHTMLAtoms::media ||
+                      aName == nsHTMLAtoms::type));
   }
 
   return rv;
@@ -253,7 +257,11 @@ nsHTMLStyleElement::UnsetAttr(PRInt32 aNameSpaceID, nsIAtom* aAttribute,
   nsresult rv = nsGenericHTMLElement::UnsetAttr(aNameSpaceID, aAttribute,
                                                 aNotify);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull,
+                     aNameSpaceID == kNameSpaceID_None &&
+                     (aAttribute == nsHTMLAtoms::title ||
+                      aAttribute == nsHTMLAtoms::media ||
+                      aAttribute == nsHTMLAtoms::type));
   }
 
   return rv;
diff --git a/mozilla/content/svg/content/src/nsSVGStyleElement.cpp b/mozilla/content/svg/content/src/nsSVGStyleElement.cpp
index 913e200a2cd..985abd7cc43 100644
--- a/mozilla/content/svg/content/src/nsSVGStyleElement.cpp
+++ b/mozilla/content/svg/content/src/nsSVGStyleElement.cpp
@@ -211,7 +211,11 @@ nsSVGStyleElement::SetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
   nsresult rv = nsSVGStyleElementBase::SetAttr(aNameSpaceID, aName, aPrefix,
                                                aValue, aNotify);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull,
+                     aNameSpaceID == kNameSpaceID_None &&
+                     (aName == nsSVGAtoms::title ||
+                      aName == nsSVGAtoms::media ||
+                      aName == nsSVGAtoms::type));
   }
 
   return rv;
@@ -224,7 +228,11 @@ nsSVGStyleElement::UnsetAttr(PRInt32 aNameSpaceID, nsIAtom* aAttribute,
   nsresult rv = nsSVGStyleElementBase::UnsetAttr(aNameSpaceID, aAttribute,
                                                  aNotify);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull,
+                     aNameSpaceID == kNameSpaceID_None &&
+                     (aAttribute == nsSVGAtoms::title ||
+                      aAttribute == nsSVGAtoms::media ||
+                      aAttribute == nsSVGAtoms::type));
   }
 
   return rv;
diff --git a/mozilla/content/xml/content/src/nsXMLStylesheetPI.cpp b/mozilla/content/xml/content/src/nsXMLStylesheetPI.cpp
index c83017e596a..1cec89e4fe6 100644
--- a/mozilla/content/xml/content/src/nsXMLStylesheetPI.cpp
+++ b/mozilla/content/xml/content/src/nsXMLStylesheetPI.cpp
@@ -138,7 +138,7 @@ nsXMLStylesheetPI::SetNodeValue(const nsAString& aNodeValue)
 {
   nsresult rv = nsGenericDOMDataNode::SetNodeValue(aNodeValue);
   if (NS_SUCCEEDED(rv)) {
-    UpdateStyleSheet();
+    UpdateStyleSheet(nsnull, nsnull, PR_TRUE);
   }
   return rv;
 }