Support custom V8 bindings on WebWorker threads (issue #451).

- Add CefRenderProcessHandler callbacks for WebWorker context creation, release and uncaught exceptions.
- Add CefTaskRunner class that supports posting of tasks to standard threads and WebWorker threads.
- Organize V8 internal state information on a per-thread/per-Isolate basis.
- Add webkit_451.patch that provides the WebKit implementation.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@972 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/renderer/render_process_observer.h

@@ -1,4 +1,4 @@
-// Copyright (c) 2012 The Chromium Embedded Framework Authors.
+// Copyright (c) 2013 The Chromium Embedded Framework Authors.
 // Portions copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
@@ -20,6 +20,7 @@ class CefRenderProcessObserver : public content::RenderProcessObserver {
   // RenderProcessObserver implementation.
   virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void WebKitInitialized() OVERRIDE;
+  virtual void OnRenderProcessShutdown() OVERRIDE;
 
  private:
   // Message handlers called on the render thread.