workers: Introduce a WorkerMessageFilter to ease routing/processing worker messages.

content/child/navigator_connect/navigator_connect_dispatcher.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_CHILD_NAVIGATOR_CONNECT_NAVIGATOR_CONNECT_DISPATCHER_H_
 #define CONTENT_CHILD_NAVIGATOR_CONNECT_NAVIGATOR_CONNECT_DISPATCHER_H_
 
-#include "content/child/child_message_filter.h"
-
-namespace base {
-class MessageLoopProxy;
-}
+#include "content/child/worker_thread_message_filter.h"
 
 namespace content {
 
-class ThreadSafeSender;
-
 // Receives IPC messages from the browser process and dispatches them to the
 // correct thread specific NavigatorConnectProvider.
-class NavigatorConnectDispatcher : public ChildMessageFilter {
+class NavigatorConnectDispatcher : public WorkerThreadMessageFilter {
  public:
   explicit NavigatorConnectDispatcher(ThreadSafeSender* thread_safe_sender);
 
  private:
   ~NavigatorConnectDispatcher() override;
 
-  // ChildMessageFilter implementation:
-  base::TaskRunner* OverrideTaskRunnerForMessage(
-      const IPC::Message& msg) override;
-  bool OnMessageReceived(const IPC::Message& msg) override;
-
-  scoped_refptr<base::MessageLoopProxy> main_thread_loop_proxy_;
-  scoped_refptr<ThreadSafeSender> thread_safe_sender_;
+  // WorkerThreadMessageFilter:
+  bool ShouldHandleMessage(const IPC::Message& msg) const override;
+  void OnFilteredMessageReceived(const IPC::Message& msg) override;
+  bool GetWorkerThreadIdForMessage(const IPC::Message& msg,
+                                   int* ipc_thread_id) override;
 
   DISALLOW_COPY_AND_ASSIGN(NavigatorConnectDispatcher);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_NAVIGATOR_CONNECT_NAVIGATOR_CONNECT_DISPATCHER_H_