[Video] Pause videos with no audio when in the background.

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 <memory>
@@ skipping 350 matching lines @@
 
   void CreateWatchTimeReporter();
 
   // Returns true if the player is hidden.
   bool IsHidden() const;
 
   // Return whether |pipeline_metadata_| is compatible with an overlay. This
   // is intended for android.
   bool DoesOverlaySupportMetadata() const;
 
+  // Whether the media should be paused when hidden.
+  bool ShouldPauseWhenHidden() const;
+
   blink::WebLocalFrame* frame_;
 
   // The playback state last reported to |delegate_|, to avoid setting duplicate
   // states. (Which can have undesired effects like resetting the idle timer.)
   DelegateState delegate_state_;
 
   // Set when OnSuspendRequested() is called with |must_suspend| unset.
   bool is_idle_;
 
   // Set when OnSuspendRequested() is called with |must_suspend| set.
@@ skipping 43 matching lines @@
   // to hang the render thread during pause(), we record the time at the same
   // time we pause and then return that value in currentTime().  Otherwise our
   // clock can creep forward a little bit while the asynchronous
   // SetPlaybackRate(0) is being executed.
   double playback_rate_;
 
   // Set while paused. |paused_time_| is only valid when |paused_| is true.
   bool paused_;
   base::TimeDelta paused_time_;
 
+  // Set if paused automatically when hidden and need to resume when visible.
+  // Reset if paused for any other reason.
+  bool paused_when_hidden_;
+
   // Set when starting, seeking, and resuming (all of which require a Pipeline
   // seek). |seek_time_| is only valid when |seeking_| is true.
   bool seeking_;
   base::TimeDelta seek_time_;
 
   // Set when doing a restart (a suspend and resume in sequence) of the pipeline
   // in order to destruct and reinitialize the decoders. This is separate from
   // |pending_resume_| and |pending_suspend_| because they can be elided in
   // certain cases, whereas for a restart they must happen.
   // TODO(sandersd,watk): Create a simpler interface for a pipeline restart.
@@ skipping 147 matching lines @@
 
   // Whether the player is currently in autoplay muted state.
   bool autoplay_muted_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_WEBMEDIAPLAYER_IMPL_H_