Bug 765620 - When parsing from stream without executing scripts, avoid script execution-related tree ops. r=smaug

parser/html/nsHtml5TreeOpExecutor.cpp

@@ -759,6 +759,13 @@ nsHtml5TreeOpExecutor::StartLayout() {
 void
 nsHtml5TreeOpExecutor::RunScript(nsIContent* aScriptElement)
 {
+  if (mRunsToCompletion) {
+    // We are in createContextualFragment() or in the upcoming document.parse().
+    // Do nothing. Let's not even mark scripts malformed here, because that
+    // could cause serialization weirdness later.
+    return;
+  }
+
   NS_ASSERTION(aScriptElement, "No script to run");
   nsCOMPtr<nsIScriptElement> sele = do_QueryInterface(aScriptElement);
   
@@ -770,13 +777,6 @@ nsHtml5TreeOpExecutor::RunScript(nsIContent* aScriptElement)
     return;
   }
   
-  if (mPreventScriptExecution) {
-    sele->PreventExecution();
-  }
-  if (mRunsToCompletion) {
-    return;
-  }
-
   if (sele->GetScriptDeferred() || sele->GetScriptAsync()) {
     DebugOnly<bool> block = sele->AttemptToExecute();
     NS_ASSERTION(!block, "Defer or async script tried to block.");