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

media/blink/webmediaplayer_impl.cc

Index: media/blink/webmediaplayer_impl.cc
diff --git a/media/blink/webmediaplayer_impl.cc b/media/blink/webmediaplayer_impl.cc
index b6a56c2cd26dce38c4fc4676e610e77460f315e6..1ab167461b5da4ef94aef05f80e29134822cbfcb 100644
--- a/media/blink/webmediaplayer_impl.cc
+++ b/media/blink/webmediaplayer_impl.cc
@@ -205,6 +205,7 @@ WebMediaPlayerImpl::WebMediaPlayerImpl(
       opaque_(false),
       playback_rate_(0.0),
       paused_(true),
+      paused_when_hidden_(false),
       seeking_(false),
       pending_suspend_resume_cycle_(false),
       ended_(false),
@@ -448,6 +449,9 @@ void WebMediaPlayerImpl::pause() {
   // paused state.
   paused_ = true;
 
+  // No longer paused because it was hidden.
+  paused_when_hidden_ = false;
+
 #if defined(OS_ANDROID)  // WMPI_CAST
   if (isRemote()) {
     cast_impl_.pause();
@@ -1336,12 +1340,19 @@ void WebMediaPlayerImpl::OnVideoOpacityChange(bool opaque) {
 void WebMediaPlayerImpl::OnHidden() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
-  if (IsBackgroundVideoTrackOptimizationEnabled())
-    selectedVideoTrackChanged(nullptr);
-
   if (watch_time_reporter_)
     watch_time_reporter_->OnHidden();
 
+  if (IsBackgroundVideoTrackOptimizationEnabled()) {
+    if (ShouldPauseWhenHidden()) {
+      OnPause();
+      paused_when_hidden_ = true;

[sandersd (OOO until July 31), 2017/01/06 01:44:15]

Probably needs a comment to explain that the order of these lines is important.

This is also relying on pause() to call UpdatePlayState(), which works, but
isn't obvious.

[whywhat, 2017/01/06 16:59:31]

Done. Alternatively I could perhaps take the most of pause() into its own method
(pause_internal() ?) and call that along with setting the flag, calling
UpdatePlayState() and client_->UpdatePlayState() -- sounds like some duplication
but no hidden dependencies. OnPause() call below would need something similar
too though.

+      return;
+    }
+
+    selectedVideoTrackChanged(nullptr);
+  }
+
   UpdatePlayState();
 
   // Schedule suspended playing media to be paused if the user doesn't come back
@@ -1354,10 +1365,17 @@ void WebMediaPlayerImpl::OnShown() {
   if (watch_time_reporter_)
     watch_time_reporter_->OnShown();
 
-  if (IsBackgroundVideoTrackOptimizationEnabled() &&
-      client_->hasSelectedVideoTrack()) {
-    WebMediaPlayer::TrackId trackId = client_->getSelectedVideoTrackId();
-    selectedVideoTrackChanged(&trackId);
+  if (IsBackgroundVideoTrackOptimizationEnabled()) {
+    if (paused_when_hidden_) {
+      paused_when_hidden_ = false;
+      OnPlay();
+      return;
+    }
+
+    if (client_->hasSelectedVideoTrack()) {
+      WebMediaPlayer::TrackId trackId = client_->getSelectedVideoTrackId();
+      selectedVideoTrackChanged(&trackId);
+    }
   }
 
   must_suspend_ = false;
@@ -2040,4 +2058,13 @@ void WebMediaPlayerImpl::ActivateViewportIntersectionMonitoring(bool activate) {
   client_->activateViewportIntersectionMonitoring(activate);
 }
 
+bool WebMediaPlayerImpl::ShouldPauseWhenHidden() const {
+#if defined(OS_ANDROID)  // WMPI_CAST
+  if (isRemote())
+    return false;
+#endif  // defined(OS_ANDROID)  // WMPI_CAST
+
+  return hasVideo() && !hasAudio();
+}
+
 }  // namespace media