Add ChildMessageFilter, a base class for renderer/worker cross-thread MessageFilter

content/child/worker_thread_task_runner.cc

Index: content/child/worker_thread_task_runner.cc
diff --git a/content/child/worker_thread_task_runner.cc b/content/child/worker_thread_task_runner.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fb2a5a89c9007dfef3848cec316ac18776bc4b67
--- /dev/null
+++ b/content/child/worker_thread_task_runner.cc
@@ -0,0 +1,40 @@
+// Copyright 2013 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.
+
+#include "content/child/worker_thread_task_runner.h"
+
+#include "base/logging.h"
+#include "webkit/child/worker_task_runner.h"
+
+using webkit_glue::WorkerTaskRunner;
+
+namespace content {
+
+WorkerThreadTaskRunner::WorkerThreadTaskRunner(int worker_thread_id)
+    : worker_thread_id_(worker_thread_id) {
+}
+
+scoped_refptr<WorkerThreadTaskRunner> WorkerThreadTaskRunner::current() {
+  int worker_thread_id = WorkerTaskRunner::Instance()->CurrentWorkerId();
+  if (!worker_thread_id)
+    return scoped_refptr<WorkerThreadTaskRunner>();
+  return make_scoped_refptr(new WorkerThreadTaskRunner(worker_thread_id));
+}
+
+bool WorkerThreadTaskRunner::PostDelayedTask(
+    const tracked_objects::Location& /* from_here */,
+    const base::Closure& task,
+    base::TimeDelta delay) {
+  // Currently non-zero delay is not supported.
+  DCHECK(!delay.ToInternalValue());
+  return WorkerTaskRunner::Instance()->PostTask(worker_thread_id_, task);
+}
+
+bool WorkerThreadTaskRunner::RunsTasksOnCurrentThread() const {
+  return worker_thread_id_ == WorkerTaskRunner::Instance()->CurrentWorkerId();
+}
+
+WorkerThreadTaskRunner::~WorkerThreadTaskRunner() {}
+
+}  // namespace content