Backed out changeset 8506b25206cf (bug 504311) because the test added uses enablePrivilege which hangs tinderbox asking for privileges.

layout/style/crashtests/504311-1.xul

@@ -1,24 +0,0 @@
-<?xml version="1.0"?>
-<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
-
-<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-        onload="f()">
-
-	<script type="text/javascript">
-		<![CDATA[
-			function f ()
-			{
-                netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-                var tb = document. getElementById ("tb01");
-				var inputField = tb. inputField;
-				var editor = inputField. QueryInterface (Components. interfaces. nsIDOMNSEditableElement). editor;
-				editor = editor. QueryInterface (Components. interfaces. nsIEditor);
-				editor = editor. QueryInterface (Components. interfaces. nsIPlaintextEditor);
-				editor. wrapWidth = -1;
-			}
-		]]>
-	</script>
-	
-	<textbox id="tb01" multiline="true"/>
-
-</window>

layout/style/crashtests/crashtests.list

@@ -39,4 +39,3 @@ load 473914-1.html
 skip load long-url-list-stack-overflow.html # skipped due to being slow (bug 477490)
 load 495269-1.html
 load 495269-2.html
-load 504311-1.xul

layout/style/nsStyleStruct.cpp

@@ -1873,14 +1873,13 @@ nsStyleText::~nsStyleText(void) { }
 
 nsChangeHint nsStyleText::CalcDifference(const nsStyleText& aOther) const
 {
-  if (NewlineIsSignificant() != aOther.NewlineIsSignificant()) {
+  if (mWhiteSpace != aOther.mWhiteSpace) {
     // This may require construction of suppressed text frames
     return NS_STYLE_HINT_FRAMECHANGE;
   }
 
   if ((mTextAlign != aOther.mTextAlign) ||
       (mTextTransform != aOther.mTextTransform) ||
-      (mWhiteSpace != aOther.mWhiteSpace) ||
       (mWordWrap != aOther.mWordWrap) ||
       (mLetterSpacing != aOther.mLetterSpacing) ||
       (mLineHeight != aOther.mLineHeight) ||