[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 a105327d0635b16c4d2fdc937a2cb7a89c32fa91..cccbcf8dc79e7d037d2e362999e394df37088b91 100644
--- a/media/blink/webmediaplayer_impl.cc
+++ b/media/blink/webmediaplayer_impl.cc
@@ -1714,7 +1714,7 @@ void WebMediaPlayerImpl::UpdatePlayState() {
 #endif
 
   bool is_suspended = pipeline_controller_.IsSuspended();
-  bool is_backgrounded = IsBackgroundedSuspendEnabled() && IsHidden();
+  bool is_backgrounded = IsHidden();
   PlayState state = UpdatePlayState_ComputePlayState(
       is_remote, is_streaming, is_suspended, is_backgrounded);
   SetDelegateState(state.delegate_state);
@@ -1837,7 +1837,11 @@ WebMediaPlayerImpl::UpdatePlayState_ComputePlayState(bool is_remote,
                                hasAudio() && IsResumeBackgroundVideosEnabled();
   bool is_background_playing =
       delegate_ && delegate_->IsPlayingBackgroundVideo();
-  bool background_suspended = !is_streaming && is_backgrounded_video &&
+  // Video-only media should always be suspended when in background.
+  bool should_suspend_background_media =
+      IsBackgroundedSuspendEnabled() || !hasAudio();
+  bool background_suspended = should_suspend_background_media &&
+                              !is_streaming && is_backgrounded_video &&
                               !(can_play_backgrounded && is_background_playing);
   bool background_pause_suspended =
       !is_streaming && is_backgrounded && paused_ && have_future_data;
@@ -1951,8 +1955,9 @@ void WebMediaPlayerImpl::FinishMemoryUsageReport(int64_t demuxer_memory_usage) {
 }
 
 void WebMediaPlayerImpl::ScheduleIdlePauseTimer() {
-  // Only schedule the pause timer if we're playing and are suspended.
-  if (paused_ || !pipeline_controller_.IsSuspended())
+  // Only schedule the pause timer if we're playing, are suspended and
+  // have audio.
+  if (paused_ || !pipeline_controller_.IsSuspended() || !hasAudio())

[sandersd (OOO until July 31), 2016/12/15 01:09:47]

This doesn't look quite right to me. The purpose of the pause timer to to define
a threshold after which suspended media becomes paused, rather than resuming
automatically when foregrounded.

This seems to say that media without audio is always resumed automatically,
which is a rather broader statement than the CL description. If this change is
necessary to avoid breaking sites, it may mean that the pause timer was a bad
idea to begin with, or that a much more involved heuristic is required.

[whywhat, 2016/12/16 01:20:24]

Well, it might be - AFAIK it only affects Android (do we suspend videos that are
offscreen on desktop atm?) and if the video is an animation with no controls,
there's no way to resume it for the user once it's paused, no?

So autoresuming the silent videos seems natural to me and that's how it worked
with WMPA IIRC. That's probably how it should work on desktop as well.

[whywhat, 2016/12/16 20:09:37]

Dan, am I correct that the timer would only trigger for videos suspended in the
background? It seems like it doesn't trigger for the audible videos even on
Android since background video playback was added and it breaks pages when
triggered silent videos. Is there any other use for it? I'm hesitant to just
remove it assuming I don't know of all the use cases.

Maybe this should be a separate change as a bug fix for Android autoplay videos
(I'd even merge it to M56 as I suspect gfycat.com is broken there too).

     return;
 
 #if defined(OS_ANDROID)