Bug 654106 - Avoid registering a script observer in the fragment parsing case. r=bzbarsky.

content/base/src/nsContentSink.cpp

@@ -287,25 +287,28 @@ nsContentSink::Init(nsIDocument* aDoc,
 
   mDocumentURI = aURI;
   mDocShell = do_QueryInterface(aContainer);
-  if (mDocShell) {
-    PRUint32 loadType = 0;
-    mDocShell->GetLoadType(&loadType);
-    mDocument->SetChangeScrollPosWhenScrollingToRef(
-      (loadType & nsIDocShell::LOAD_CMD_HISTORY) == 0);
+  mScriptLoader = mDocument->ScriptLoader();
+
+  if (!mFragmentMode) {
+    if (mDocShell) {
+      PRUint32 loadType = 0;
+      mDocShell->GetLoadType(&loadType);
+      mDocument->SetChangeScrollPosWhenScrollingToRef(
+        (loadType & nsIDocShell::LOAD_CMD_HISTORY) == 0);
+    }
+
+    // use this to avoid a circular reference sink->document->scriptloader->sink
+    nsCOMPtr<nsIScriptLoaderObserver> proxy =
+      new nsScriptLoaderObserverProxy(this);
+    NS_ENSURE_TRUE(proxy, NS_ERROR_OUT_OF_MEMORY);
+
+    mScriptLoader->AddObserver(proxy);
+
+    ProcessHTTPHeaders(aChannel);
   }
 
-  // use this to avoid a circular reference sink->document->scriptloader->sink
-  nsCOMPtr<nsIScriptLoaderObserver> proxy =
-      new nsScriptLoaderObserverProxy(this);
-  NS_ENSURE_TRUE(proxy, NS_ERROR_OUT_OF_MEMORY);
-
-  mScriptLoader = mDocument->ScriptLoader();
-  mScriptLoader->AddObserver(proxy);
-
   mCSSLoader = aDoc->CSSLoader();
 
-  ProcessHTTPHeaders(aChannel);
-
   mNodeInfoManager = aDoc->NodeInfoManager();
 
   mBackoffCount = sBackoffCount;
@@ -315,10 +318,11 @@ nsContentSink::Init(nsIDocument* aDoc,
     FavorPerformanceHint(!mDynamicLowerValue, 0);
   }
 
-  mCanInterruptParser = sCanInterruptParser;
+  // prevent DropParserAndPerfHint from unblocking onload in the fragment
+  // case
+  mCanInterruptParser = !mFragmentMode && sCanInterruptParser;
 
   return NS_OK;
-
 }
 
 NS_IMETHODIMP

content/base/src/nsContentSink.h

@@ -343,6 +343,8 @@ protected:
   // shouldn't be performing any more content model notifications,
   // since we're not longer updating our child counts.
   PRUint8 mIsDocumentObserver : 1;
+  // True if this is a fragment parser
+  PRUint8 mFragmentMode : 1;
   
   //
   // -- Can interrupt parsing members --

parser/html/nsHtml5Parser.cpp

@@ -497,6 +497,8 @@ nsHtml5Parser::ParseHtml5Fragment(const nsAString& aSourceBuffer,
   nsIURI* uri = doc->GetDocumentURI();
   NS_ENSURE_TRUE(uri, NS_ERROR_NOT_AVAILABLE);
 
+  mExecutor->EnableFragmentMode(aPreventScriptExecution);
+
   Initialize(doc, uri, nsnull, nsnull);
 
   mExecutor->SetParser(this);
@@ -516,8 +518,6 @@ nsHtml5Parser::ParseHtml5Fragment(const nsAString& aSourceBuffer,
   }
 #endif
 
-  mExecutor->EnableFragmentMode(aPreventScriptExecution);
-  
   NS_PRECONDITION(!mExecutor->HasStarted(),
                   "Tried to start parse without initializing the parser.");
   mTreeBuilder->setScriptingEnabled(mExecutor->IsScriptEnabled());

parser/html/nsHtml5TreeOpExecutor.h

@@ -124,8 +124,6 @@ class nsHtml5TreeOpExecutor : public nsContentSink,
 
     PRBool                        mCallContinueInterruptedParsingIfEnabled;
 
-    PRBool                        mFragmentMode;
-
     PRBool                        mPreventScriptExecution;
 
   public:
@@ -241,8 +239,6 @@ class nsHtml5TreeOpExecutor : public nsContentSink,
      */
     void EnableFragmentMode(PRBool aPreventScriptExecution) {
       mFragmentMode = PR_TRUE;
-      mCanInterruptParser = PR_FALSE; // prevent DropParserAndPerfHint
-                                      // from unblocking onload
       mPreventScriptExecution = aPreventScriptExecution;
     }