Use the Document rather than the Frame's execution context to install JS-based marquee elements

Source/core/html/HTMLMarqueeElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2007, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 16 matching lines @@
 #include "bindings/core/v8/V8HTMLMarqueeElement.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/frame/UseCounter.h"
 
 namespace blink {
 
 inline HTMLMarqueeElement::HTMLMarqueeElement(Document& document)
     : HTMLElement(HTMLNames::marqueeTag, document)
 {
-    v8::Handle<v8::Value> classObject = PrivateScriptRunner::installClassIfNeeded(document.frame(), "HTMLMarqueeElement");
+    v8::Handle<v8::Value> classObject = PrivateScriptRunner::installClassIfNeeded(&document, "HTMLMarqueeElement");
     RELEASE_ASSERT(!classObject.IsEmpty());

[adamk, 2014/10/22 17:38:45]

This RELEASE_ASSERT still looks scary to me. There's code in
Document::contextDocument() that'll sometimes return NULL, which would result in
a crash here. Why are we sure that it's impossible for a contextDocument's
m_frame to be non-empty? Or are we just sure that we won't be running the
HTMLMarqueeElement constructor at that time?

[haraken, 2014/10/23 00:52:05]

I think we can just remove installClassIfNeeded() completely, because
installClassIfNeeded() is lazily called when any private script API is invoked.

In this particular case, installClassIfNeeded() will be called when we call
V8HTMLMarqueeElement::PrivateScript::createdCallbackMethod(). If we don't have
any frame at that point, createdCallbackMethod() will return immediately without
doing nothing. (This is better than crashing, but it's still a wrong behavior.
We need a frame to execute a private script.)

I'll remove installClassIfNeeded() in a follow-up CL.

     UseCounter::count(document, UseCounter::HTMLMarqueeElement);
 }
 
 PassRefPtrWillBeRawPtr<HTMLMarqueeElement> HTMLMarqueeElement::create(Document& document)
 {
     RefPtrWillBeRawPtr<HTMLMarqueeElement> marqueeElement(adoptRefWillBeNoop(new HTMLMarqueeElement(document)));
     V8HTMLMarqueeElement::PrivateScript::createdCallbackMethod(document.frame(), marqueeElement.get());
     return marqueeElement.release();
 }
 
@@ skipping 14 matching lines @@
 
 void HTMLMarqueeElement::removedFrom(ContainerNode* insertionPoint)
 {
     HTMLElement::removedFrom(insertionPoint);
     if (insertionPoint->inDocument()) {
         V8HTMLMarqueeElement::PrivateScript::detachedCallbackMethod(insertionPoint->document().frame(), this);
     }
 }
 
 } // namespace blink