Mojo: Add BindingsSupportImpl on top of HandleWatcher

mojo/common/handle_watcher.h

 // 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.
 
 #ifndef MOJO_COMMON_HANDLE_WATCHER_H_
 #define MOJO_COMMON_HANDLE_WATCHER_H_
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 20 matching lines @@
   ~HandleWatcher();
 
   // Starts listening for |handle|. This implicitly invokes Stop(). In other
   // words, Start() performs one asynchronous watch at a time. It is ok to call
   // Start() multiple times, but it cancels any existing watches. |callback| is
   // notified when the handle is ready, invalid or deadline has passed and is
   // notified on the thread Start() was invoked on.
   void Start(MojoHandle handle,
              MojoWaitFlags wait_flags,
              MojoDeadline deadline,
-             const base::Closure& callback);
+             const base::Callback<void(MojoResult)>& callback);
 
   // Stops listening. Does nothing if not in the process of listening.
   void Stop();
 
   // Returns now. Used internally; generally not useful.
   static base::TimeTicks NowTicks();
 
   // Converts a MojoDeadline into a TimeTicks.
   static base::TimeTicks MojoDeadlineToTimeTicks(MojoDeadline deadline);
 
  private:
   friend class test::HandleWatcherTest;
   struct StartState;
 
   // See description of |StartState::weak_factory| for details.
-  void OnHandleReady();
+  void OnHandleReady(MojoResult result);
 
   // If non-NULL Start() has been invoked.
   scoped_ptr<StartState> start_state_;
 
   // Used for getting the time. Only set by tests.
   static base::TickClock* tick_clock_;
 
   DISALLOW_COPY_AND_ASSIGN(HandleWatcher);
 };
 
 }  // namespace common
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_HANDLE_WATCHER_H_