Add MojoVideoDecoder.

media/renderers/default_renderer_factory.cc

 // 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.
 
 #include "media/renderers/default_renderer_factory.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 38 matching lines @@
   // Create our audio decoders and renderer.
   ScopedVector<AudioDecoder> audio_decoders;
 
 #if !defined(MEDIA_DISABLE_FFMPEG)
   audio_decoders.push_back(
       new FFmpegAudioDecoder(media_task_runner, media_log_));
 #endif
 
   audio_decoders.push_back(new OpusAudioDecoder(media_task_runner));
 
+  // Use an external decoder only if we cannot otherwise decode in the
+  // renderer.
   if (decoder_factory_)
     decoder_factory_->CreateAudioDecoders(&audio_decoders);
 
   return audio_decoders;
 }
 
 ScopedVector<VideoDecoder> DefaultRendererFactory::CreateVideoDecoders(
     const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
     const RequestSurfaceCB& request_surface_cb,
     GpuVideoAcceleratorFactories* gpu_factories) {
   // Create our video decoders and renderer.
   ScopedVector<VideoDecoder> video_decoders;
 
+  // Prefer an external decoder since one will only exist if it is hardware
+  // accelerated.
+  if (decoder_factory_)
+    decoder_factory_->CreateVideoDecoders(&video_decoders);
+
   // |gpu_factories_| requires that its entry points be called on its
   // |GetTaskRunner()|.  Since |pipeline_| will own decoders created from the
   // factories, require that their message loops are identical.
   DCHECK(!gpu_factories ||
          (gpu_factories->GetTaskRunner() == media_task_runner.get()));
 
   if (gpu_factories)
     video_decoders.push_back(
         new GpuVideoDecoder(gpu_factories, request_surface_cb));
 
 #if !defined(MEDIA_DISABLE_LIBVPX)
   video_decoders.push_back(new VpxVideoDecoder());
 #endif
 
 #if !defined(MEDIA_DISABLE_FFMPEG) && !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
   video_decoders.push_back(new FFmpegVideoDecoder());
 #endif
 
-  if (decoder_factory_)
-    decoder_factory_->CreateVideoDecoders(&video_decoders);
-
   return video_decoders;
 }
 
 scoped_ptr<Renderer> DefaultRendererFactory::CreateRenderer(
     const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
     const scoped_refptr<base::TaskRunner>& worker_task_runner,
     AudioRendererSink* audio_renderer_sink,
     VideoRendererSink* video_renderer_sink,
     const RequestSurfaceCB& request_surface_cb) {
   DCHECK(audio_renderer_sink);
@@ skipping 10 matching lines @@
   scoped_ptr<VideoRenderer> video_renderer(new VideoRendererImpl(
       media_task_runner, worker_task_runner, video_renderer_sink,
       CreateVideoDecoders(media_task_runner, request_surface_cb, gpu_factories),
       true, gpu_factories, media_log_));
 
   return scoped_ptr<Renderer>(new RendererImpl(
       media_task_runner, std::move(audio_renderer), std::move(video_renderer)));
 }
 
 }  // namespace media