Convert MediaLog from being ref counted to owned by WebMediaPlayer.

media/blink/webmediaplayer_params.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 MEDIA_BLINK_WEBMEDIAPLAYER_PARAMS_H_
 #define MEDIA_BLINK_WEBMEDIAPLAYER_PARAMS_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
+#include "media/base/media_log.h"
 #include "media/base/media_observer.h"
 #include "media/blink/media_blink_export.h"
 #include "media/filters/context_3d.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 class TaskRunner;
 }
 
 namespace blink {
 class WebContentDecryptionModule;
 }
 
 namespace media {
 
 class SwitchableAudioRendererSink;
-class MediaLog;
 class SurfaceManager;
 
 // Holds parameters for constructing WebMediaPlayerImpl without having
 // to plumb arguments through various abstraction layers.
 class MEDIA_BLINK_EXPORT WebMediaPlayerParams {
  public:
   typedef base::Callback<void(const base::Closure&)> DeferLoadCB;
   typedef base::Callback<Context3D()> Context3DCB;
 
   // Callback to tell V8 about the amount of memory used by the WebMediaPlayer
   // instance.  The input parameter is the delta in bytes since the last call to
   // AdjustAllocatedMemoryCB and the return value is the total number of bytes
   // used by objects external to V8.  Note: this value includes things that are
   // not the WebMediaPlayer!
   typedef base::Callback<int64_t(int64_t)> AdjustAllocatedMemoryCB;
 
   // |defer_load_cb|, |audio_renderer_sink|, |compositor_task_runner|, and
   // |context_3d_cb| may be null.
   WebMediaPlayerParams(
+      std::unique_ptr<MediaLog> media_log,
       const DeferLoadCB& defer_load_cb,
       const scoped_refptr<SwitchableAudioRendererSink>& audio_renderer_sink,
-      const scoped_refptr<MediaLog>& media_log,
       const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
       const scoped_refptr<base::TaskRunner>& worker_task_runner,
       const scoped_refptr<base::SingleThreadTaskRunner>& compositor_task_runner,
       const Context3DCB& context_3d,
       const AdjustAllocatedMemoryCB& adjust_allocated_memory_cb,
       blink::WebContentDecryptionModule* initial_cdm,
       SurfaceManager* surface_manager,
       base::WeakPtr<MediaObserver> media_observer,
       base::TimeDelta max_keyframe_distance_to_disable_background_video,
       base::TimeDelta max_keyframe_distance_to_disable_background_video_mse,
       bool enable_instant_source_buffer_gc,
       bool allow_suspend,
       bool embedded_media_experience_enabled);
 
   ~WebMediaPlayerParams();
 
   DeferLoadCB defer_load_cb() const { return defer_load_cb_; }
 
   const scoped_refptr<SwitchableAudioRendererSink>& audio_renderer_sink()
       const {
     return audio_renderer_sink_;
   }
 
-  const scoped_refptr<MediaLog>& media_log() const {
-    return media_log_;
-  }
+  std::unique_ptr<MediaLog> media_log() { return std::move(media_log_); }

[chcunningham, 2017/04/18 23:29:12]

The sideeffects are a little subtle for anyone not looking at the
implementation. Do you think its still proper to name this media_log() as
opposed to something like TakeMediaLog()?

[DaleCurtis, 2017/04/18 23:55:45]

Done, but I don't think it matters. It's only used in one place.

 
   const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner() const {
     return media_task_runner_;
   }
 
   const scoped_refptr<base::TaskRunner> worker_task_runner() const {
     return worker_task_runner_;
   }
 
   const scoped_refptr<base::SingleThreadTaskRunner>& compositor_task_runner()
@@ skipping 32 matching lines @@
 
   bool allow_suspend() const { return allow_suspend_; }
 
   bool embedded_media_experience_enabled() const {
     return embedded_media_experience_enabled_;
   }
 
  private:
   DeferLoadCB defer_load_cb_;
   scoped_refptr<SwitchableAudioRendererSink> audio_renderer_sink_;
-  scoped_refptr<MediaLog> media_log_;
+  std::unique_ptr<MediaLog> media_log_;
   scoped_refptr<base::SingleThreadTaskRunner> media_task_runner_;
   scoped_refptr<base::TaskRunner> worker_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;
   Context3DCB context_3d_cb_;
   AdjustAllocatedMemoryCB adjust_allocated_memory_cb_;
 
   blink::WebContentDecryptionModule* initial_cdm_;
   SurfaceManager* surface_manager_;
   base::WeakPtr<MediaObserver> media_observer_;
   base::TimeDelta max_keyframe_distance_to_disable_background_video_;
   base::TimeDelta max_keyframe_distance_to_disable_background_video_mse_;
   bool enable_instant_source_buffer_gc_;
   const bool allow_suspend_;
   const bool embedded_media_experience_enabled_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebMediaPlayerParams);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_WEBMEDIAPLAYER_PARAMS_H_