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

tests/unittests/test_handler.cc

@@ -1,4 +1,4 @@
-// Copyright (c) 2011 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.
 
@@ -130,6 +130,12 @@ void WaitForThread(CefThreadId thread_id) {
   event.Wait();
 }
 
+void WaitForThread(CefRefPtr<CefTaskRunner> task_runner) {
+  base::WaitableEvent event(true, false);
+  task_runner->PostTask(NewCefRunnableFunction(&NotifyEvent, &event));
+  event.Wait();
+}
+
 bool TestFailed() {
   CefRefPtr<CefCommandLine> command_line =
       CefCommandLine::GetGlobalCommandLine();