Introduce content::ChildMessageFilter.

content/child/child_message_filter.cc

+// 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/child_message_filter.h"
+
+#include "content/child/child_thread.h"
+#include "content/child/thread_safe_sender.h"
+
+namespace content {
+
+ChildMessageFilter::Internal::Internal(ChildMessageFilter* filter)
+    : filter_(filter) {}
+
+ChildMessageFilter::Internal::~Internal() {}
+
+bool ChildMessageFilter::Internal::OnMessageReceived(
+    const IPC::Message& message) {
+  scoped_refptr<base::TaskRunner> runner =
+      filter_->OverrideTaskRunnerForMessage(message);
+  if (runner) {
+    runner->PostTask(
+        FROM_HERE,
+        base::Bind(base::IgnoreResult(&ChildMessageFilter::OnMessageReceived),
+                   filter_,
+                   message));
+    return true;
+  }
+
+  return filter_->OnMessageReceived(message);
+}
+
+
+ChildMessageFilter::ChildMessageFilter()
+    : internal_(new Internal(this)),
+      thread_safe_sender_(ChildThread::current()->thread_safe_sender()) {}
+
+ChildMessageFilter::~ChildMessageFilter() {}
+
+bool ChildMessageFilter::Send(IPC::Message* message) {
+  return thread_safe_sender_->Send(message);
+}
+
+base::TaskRunner* ChildMessageFilter::OverrideTaskRunnerForMessage(
+    const IPC::Message& message) {
+  return NULL;
+}
+
+}  // namespace content