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/thread_util.h

@@ -1,4 +1,4 @@
-// Copyright (c) 2012 The Chromium Embedded Framework Authors. All rights
+// Copyright (c) 2013 The Chromium Embedded Framework Authors. All rights
 // reserved. Use of this source code is governed by a BSD-style license that
 // can be found in the LICENSE file.
 
@@ -28,7 +28,8 @@
     return; \
   }
 
-#define CEF_RENDER_LOOP() (CefContentRendererClient::Get()->render_loop())
+#define CEF_RENDER_LOOP() \
+    (CefContentRendererClient::Get()->render_task_runner())
 
 #define CEF_POST_TASK_RT(task) \
     CEF_RENDER_LOOP()->PostTask(FROM_HERE, task)