Convert MediaWebContentsObsever to be the client of WakeLock mojo interface.

content/browser/media/media_web_contents_observer.h

Index: content/browser/media/media_web_contents_observer.h
diff --git a/content/browser/media/media_web_contents_observer.h b/content/browser/media/media_web_contents_observer.h
index 3a2a0d3a5c3c8b8b8dc2c0d3de3c532eb58a4c05..4ad7db05a6d727cdbd493dc2d00d2123b186953e 100644
--- a/content/browser/media/media_web_contents_observer.h
+++ b/content/browser/media/media_web_contents_observer.h
@@ -15,15 +15,12 @@
 #include "content/browser/media/session/media_session_controllers_manager.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "device/wake_lock/public/interfaces/wake_lock_service.mojom.h"
 
 #if defined(OS_ANDROID)
 #include "ui/android/view_android.h"
 #endif  // OS_ANDROID
 
-namespace device {
-class PowerSaveBlocker;
-}  // namespace device
-
 namespace media {
 enum class MediaContentType;
 }  // namespace media
@@ -63,12 +60,12 @@ class CONTENT_EXPORT MediaWebContentsObserver : public WebContentsObserver {
   // fullscreening video element to the same place.
   void RequestPersistentVideo(bool value);
 
-  bool has_audio_power_save_blocker_for_testing() const {
-    return !!audio_power_save_blocker_;
+  bool has_audio_wake_lock_for_testing() const {
+    return has_audio_wake_lock_for_testing_;

[DaleCurtis, 2017/05/02 17:08:42]

Why change this? YOu don't need the bool variables if you keep the
!!audio_wake_lock_, etc.

[ke.he, 2017/05/04 11:58:24]

The "mojo::MakeRequest(&audio_wake_lock_)" is always called, so
"audio_wake_lock_.get()" is always non-nullptr.

   }
 
-  bool has_video_power_save_blocker_for_testing() const {
-    return !!video_power_save_blocker_;
+  bool has_video_wake_lock_for_testing() const {
+    return has_video_wake_lock_for_testing_;
   }
 
  protected:
@@ -91,17 +88,24 @@ class CONTENT_EXPORT MediaWebContentsObserver : public WebContentsObserver {
                                           int delegate_id,
                                           bool is_fullscreen);
 
-  // Clear |render_frame_host|'s tracking entry for its power save blockers.
-  void ClearPowerSaveBlockers(RenderFrameHost* render_frame_host);
+  // Clear |render_frame_host|'s tracking entry for its WakeLocks.
+  void ClearWakeLocks(RenderFrameHost* render_frame_host);
+
+  device::mojom::WakeLockServicePtr& GetAudioWakeLock();

[DaleCurtis, 2017/05/02 17:08:42]

Return device::mojom::WakeLockService* instead? Per-style we don't return
non-const &.

[ke.he, 2017/05/04 11:58:23]

Done.

+  device::mojom::WakeLockServicePtr& GetVideoWakeLock();
+  bool has_audio_wake_lock_for_testing_;

[DaleCurtis, 2017/05/02 17:08:42]

Variables below functions.

[ke.he, 2017/05/04 11:58:23]

Done.

+  bool has_video_wake_lock_for_testing_;
+
+  // Try to request audio wake lock.

[DaleCurtis, 2017/05/02 17:08:42]

These comments aren't really useful, so no need for them.

[ke.he, 2017/05/04 11:58:23]

Done.

+  void LockAudio();
+  // Try to request video wake lock.
+  void LockVideo();
 
-  // Creates an audio or video power save blocker respectively.
-  void CreateAudioPowerSaveBlocker();
-  void CreateVideoPowerSaveBlocker();
+  // Cancel the video wake lock if |active_video_players_| is empty.
+  void MaybeCancelVideoLock();
 
-  // Releases the audio power save blockers if |active_audio_players_| is empty.
-  // Likewise, releases the video power save blockers if |active_video_players_|
-  // is empty.
-  void MaybeReleasePowerSaveBlockers();
+  // Cancel the audio wake lock.
+  void CancelAudioLock();
 
   // Helper methods for adding or removing player entries in |player_map|.
   using PlayerSet = std::set<int>;
@@ -117,11 +121,11 @@ class CONTENT_EXPORT MediaWebContentsObserver : public WebContentsObserver {
                                    ActiveMediaPlayerMap* player_map,
                                    std::set<MediaPlayerId>* removed_players);
 
-  // Tracking variables and associated power save blockers for media playback.
+  // Tracking variables and associated wake locks for media playback.
   ActiveMediaPlayerMap active_audio_players_;
   ActiveMediaPlayerMap active_video_players_;
-  std::unique_ptr<device::PowerSaveBlocker> audio_power_save_blocker_;
-  std::unique_ptr<device::PowerSaveBlocker> video_power_save_blocker_;
+  device::mojom::WakeLockServicePtr audio_wake_lock_;
+  device::mojom::WakeLockServicePtr video_wake_lock_;
   base::Optional<MediaPlayerId> fullscreen_player_;
 
   MediaSessionControllersManager session_controllers_manager_;