[Video] Only start tracking foreground time if the video was resumed.

media/blink/video_frame_compositor.h

Index: media/blink/video_frame_compositor.h
diff --git a/media/blink/video_frame_compositor.h b/media/blink/video_frame_compositor.h
index 03fb4c5d489f5926b264645fb4ab342c3e247a28..0068933ad9ff2a9918dae9d743e7be0e2cec07ee 100644
--- a/media/blink/video_frame_compositor.h
+++ b/media/blink/video_frame_compositor.h
@@ -13,6 +13,7 @@
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "base/time/tick_clock.h"
+#include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "cc/layers/video_frame_provider.h"
 #include "media/base/video_renderer_sink.h"
@@ -57,6 +58,9 @@ class MEDIA_BLINK_EXPORT VideoFrameCompositor
     : public VideoRendererSink,
       NON_EXPORTED_BASE(public cc::VideoFrameProvider) {
  public:
+  // Used to report back the time when the new frame has been processed.
+  using OnNewProcessedFrameCB = base::Callback<void(base::TimeTicks)>;
+
   // |compositor_task_runner| is the task runner on which this class will live,
   // though it may be constructed on any thread.
   explicit VideoFrameCompositor(
@@ -103,10 +107,10 @@ class MEDIA_BLINK_EXPORT VideoFrameCompositor
   // PaintSingleFrame() is not also called while stopped.)
   base::TimeDelta GetCurrentFrameTimestamp() const;
 
-  // Called when the media player is brought to the foreground.
-  // Used to record the time it takes to process the first frame after that.
+  // Sets the callback to be run when the new frame has been processed. The
+  // callback is only run once and then reset.
   // Must be called on the compositor thread.
-  void SetForegroundTime(base::TimeTicks when);
+  void SetOnNewProcessedFrameCallback(const OnNewProcessedFrameCB& cb);
 
   void set_tick_clock_for_testing(std::unique_ptr<base::TickClock> tick_clock) {
     tick_clock_ = std::move(tick_clock);
@@ -162,7 +166,7 @@ class MEDIA_BLINK_EXPORT VideoFrameCompositor
   bool new_background_frame_;
   base::TimeDelta last_interval_;
   base::TimeTicks last_background_render_;
-  base::TimeTicks foreground_time_;
+  OnNewProcessedFrameCB new_processed_frame_cb_;
 
   // These values are set on the compositor thread, but also read on the media
   // thread when the VFC is stopped.