Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/base/pipeline_impl.h

 // Copyright (c) 2016 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_BASE_PIPELINE_IMPL_H_
 #define MEDIA_BASE_PIPELINE_IMPL_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 125 matching lines @@
   void OnVideoNaturalSizeChange(const gfx::Size& size);
   void OnVideoOpacityChange(bool opaque);
   void OnVideoAverageKeyframeDistanceUpdate();
 
   // Task completion callbacks from RendererWrapper.
   void OnSeekDone();
   void OnSuspendDone();
 
   // Parameters passed in the constructor.
   const scoped_refptr<base::SingleThreadTaskRunner> media_task_runner_;
-  const scoped_refptr<MediaLog> media_log_;
+  MediaLog* const media_log_;
 
   // Pipeline client. Valid only while the pipeline is running.
   Client* client_;
 
   // RendererWrapper instance that runs on the media thread.
   std::unique_ptr<RendererWrapper> renderer_wrapper_;
 
   // Temporary callback used for Start(), Seek(), and Resume().
   PipelineStatusCB seek_cb_;
 
@@ skipping 24 matching lines @@
 
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<PipelineImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PipelineImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_IMPL_H_