[Video] Don't pause video-only elements if they're already paused...

media/blink/webmediaplayer_impl.h

Index: media/blink/webmediaplayer_impl.h
diff --git a/media/blink/webmediaplayer_impl.h b/media/blink/webmediaplayer_impl.h
index af26096083c03d17ae07222189f751904a7ca3c4..ace66ad12eda52e750f45fc87f957f6f19121194 100644
--- a/media/blink/webmediaplayer_impl.h
+++ b/media/blink/webmediaplayer_impl.h
@@ -390,6 +390,12 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   // after the pipeline has started, otherwise returns false.
   bool IsBackgroundOptimizationCandidate() const;
 
+  // Pauses a hidden video only player to save power if possible.
+  // Must be called when either of the following happens:
+  // - right after the video was hidden,
+  // - right ater the pipeline has resumed if the video is hidden.
+  void PauseVideoIfNeeded();
+
   // Disables the video track to save power if possible.
   // Must be called when either of the following happens:
   // - right after the video was hidden,