media: Use PassInterface() in mojo media classes

media/mojo/services/mojo_renderer_impl.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 MEDIA_MOJO_SERVICES_MOJO_RENDERER_IMPL_H_
 #define MEDIA_MOJO_SERVICES_MOJO_RENDERER_IMPL_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "media/base/renderer.h"
 #include "media/mojo/interfaces/renderer.mojom.h"
 #include "mojo/public/cpp/bindings/binding.h"
+#include "mojo/public/cpp/bindings/interface_ptr_info.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace media {
 
 class DemuxerStreamProvider;
 
 // A media::Renderer that proxies to a interfaces::Renderer. That
 // interfaces::Renderer proxies back to the MojoRendererImpl via the
 // interfaces::RendererClient interface.
 //
 // This class can be created on any thread, where the |remote_renderer| is
 // connected and passed in the constructor. Then Initialize() will be called on
 // the |task_runner| and starting from that point this class is bound to the
 // |task_runner|*. That means all Renderer and RendererClient methods will be
 // called/dispached on the |task_runner|. The only exception is GetMediaTime(),
 // which can be called on any thread.
-//
-// * Threading details:
-// mojo::GetProxy() doesn't bind an InterfacePtr to a thread. Then when
-// InterfacePtr::operator->() or InterfacePtr::get() is called for the first
-// time, e.g. to call remote_renderer->Initialize(), the InterfacePtr is bound
-// the thread where the call is made.
-
 class MojoRendererImpl : public Renderer, public interfaces::RendererClient {
  public:
   MojoRendererImpl(
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
       interfaces::RendererPtr remote_renderer);
   ~MojoRendererImpl() override;
 
   // Renderer implementation.
   void Initialize(DemuxerStreamProvider* demuxer_stream_provider,
                   const PipelineStatusCB& init_cb,
@@ skipping 27 matching lines @@
   void OnInitialized(bool success);
 
   // |task_runner| on which all methods are invoked, except for GetMediaTime(),
   // which can be called on any thread.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   // Provider of audio/video DemuxerStreams. Must be valid throughout the
   // lifetime of |this|.
   DemuxerStreamProvider* demuxer_stream_provider_;
 
-  // Remote Renderer, bound to |task_runner_|.
+  // This class is constructed on one thread and used exclusively on another
+  // thread. This member is used to safely pass the RendererPtr from one thread
+  // to another. It is set in the constructor and is consumed in Initialize().
+  mojo::InterfacePtrInfo<interfaces::Renderer> remote_renderer_info_;

[yzshen1, 2016/03/22 19:15:04]

optional: interfaces::RendererPtrInfo

[xhwang, 2016/03/22 19:45:26]

Done.

+
+  // Remote Renderer, bound to |task_runner_| during Initialize().
   interfaces::RendererPtr remote_renderer_;
 
   // Binding for RendererClient, bound to the |task_runner_|.
   mojo::Binding<RendererClient> binding_;
 
   // Callbacks passed to Initialize() that we forward messages from
   // |remote_renderer_| through.
   PipelineStatusCB init_cb_;
   base::Closure ended_cb_;
   PipelineStatusCB error_cb_;
   BufferingStateCB buffering_state_cb_;
 
   // Lock used to serialize access for |time_|.
   mutable base::Lock lock_;
   base::TimeDelta time_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoRendererImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MOJO_SERVICES_MOJO_RENDERER_IMPL_H_