Convert WMPI state management to level-triggered.

media/blink/webmediaplayer_impl.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_IMPL_H_
 #define MEDIA_BLINK_WEBMEDIAPLAYER_IMPL_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 178 matching lines @@
                                     PipelineStatus status);
   gfx::Size GetCanvasSize() const;
   void SetDeviceScaleFactor(float scale_factor);
 #endif
 
   // Called from WebMediaPlayerCast.
   // TODO(hubbe): WMPI_CAST make private.
   void OnPipelineSeeked(bool time_updated);
 
  private:
+  // Play states that are meaningful to |delegate_|.
+  // TODO(sandersd): This should move into WebMediaPlayerDelegate.

[DaleCurtis, 2016/03/25 23:21:23]

Why not do it in this patch set then?

[sandersd (OOO until July 31), 2016/03/25 23:42:42]

The easy answer is that the Play state has additional metadata to be passed, and
so the correct API is not clear. (I suspect that the TODO for duration change
will inform that choice though.)

There is also a related refactoring for the other direction:
OnHidden()/OnShown()/OnSuspendRequested() should be merged into a similar set of
'suspend reasons'. There is a different problem there: idle and background can
be true at the same time, so the best API isn't obvious either.

+  enum class PlayState {
+    GONE,
+    PLAYING,
+    PAUSED,
+    ENDED,
+  };
+
   void OnPipelineSuspended();
-  void OnPipelineResumed();
   void OnPipelineEnded();
   void OnPipelineError(PipelineStatus error);
   void OnPipelineMetadata(PipelineMetadata metadata);
   void OnPipelineBufferingStateChanged(BufferingState buffering_state);
   void OnDemuxerOpened();
   void OnAddTextTrack(const TextTrackConfig& config,
                       const AddTextTrackDoneCB& done_cb);
 
   // Actually seek. Avoids causing |should_notify_time_changed_| to be set when
   // |time_updated| is false.
@@ skipping 56 matching lines @@
   // is not available.
   void OnWaitingForDecryptionKey();
 
   // Sets |cdm_context| on the pipeline and fires |cdm_attached_cb| when done.
   // Parameter order is reversed for easy binding.
   void SetCdm(const CdmAttachedCB& cdm_attached_cb, CdmContext* cdm_context);
 
   // Called when a CDM has been attached to the |pipeline_|.
   void OnCdmAttached(bool success);
 
-  // Notifies |delegate_| that playback has started or was paused; also starts
-  // or stops the memory usage reporting timer respectively.
-  void NotifyPlaybackStarted();
-  void NotifyPlaybackPaused();
+  // Inspectes the current playback state and:
+  //   - notifies |delegate_|,
+  //   - toggles the memory usage reporting timer, and
+  //   - toggles suspend/resume as necessary.
+  // This method should be called any time its dependent variables are changed.
+  void UpdatePlayState();
+
+  // Internal to UpdatePlayState()
+  // TODO(sandersd): Move this into |delegate_|.
+  void UpdatePlayState_SetPlayState(PlayState new_state);
 
   // Called at low frequency to tell external observers how much memory we're
   // using for video playback.  Called by |memory_usage_reporting_timer_|.
   // Memory usage reporting is done in two steps, because |demuxer_| must be
   // accessed on the media thread.
   void ReportMemoryUsage();
   void FinishMemoryUsageReport(int64_t demuxer_memory_usage);
 
-  // Indicates if automatic resumption of a suspended playback is allowed.
-  bool IsAutomaticResumeAllowed();
+  blink::WebLocalFrame* frame_;
 
-  blink::WebLocalFrame* frame_;
+  // The play state last reported to |delegate_|.
+  PlayState play_state_;
+
+  // Set when OnSuspendRequested() is called with |must_suspend| unset.
+  bool idle_suspend_;
+
+  // Set when OnSuspendRequested() is called with |must_suspend| set.
+  bool must_suspend_;
 
   // TODO(hclam): get rid of these members and read from the pipeline directly.
   blink::WebMediaPlayer::NetworkState network_state_;
   blink::WebMediaPlayer::ReadyState ready_state_;
+  blink::WebMediaPlayer::ReadyState highest_ready_state_;
 
   // Preload state for when |data_source_| is created after setPreload().
   BufferedDataSource::Preload preload_;
 
   // Buffering strategy for when |data_source_| is created after
   // setBufferingStrategy().
   BufferedDataSource::BufferingStrategy buffering_strategy_;
 
   // Task runner for posting tasks on Chrome's main thread. Also used
   // for DCHECKs so methods calls won't execute in the wrong thread.
@@ skipping 132 matching lines @@
   // started; prevents us from spuriously logging errors that are transient or
   // unimportant.
   bool suppress_destruction_errors_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_WEBMEDIAPLAYER_IMPL_H_