[Video] Record the results of background video optimization checks.

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 5194a7e1ea5c611ce933e6562944b80f3dfd71b5..ec394b8016733124987cb6a964bb7df94ae09dd3 100644
--- a/media/blink/webmediaplayer_impl.h
+++ b/media/blink/webmediaplayer_impl.h
@@ -458,6 +458,33 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   // handling a src= or MSE based playback.
   void RecordUnderflowDuration(base::TimeDelta duration);
 
+  // Indicates why ShouldPauseVideoWhenHidden() or
+  // ShouldDisableVideoWhenHidden() failed or succeeded for metrics recording.
+  // Must be in sync with the MediaBackgroundOptimizationCandidacyResult enum
+  // in histograms.xml.
+  enum BackgroundOptimizationResult {
+    // Was optimized because shorter than the threshold.
+    SUCCESS_FOR_DURATION,
+    // Was optimized because keyframe distance is shorter than the threshold.
+    SUCCESS_FOR_KEYFRAME_DISTANCE,
+    // Was optimized because it doesn't have audio ignoring the threshold.
+    SUCCESS_FOR_VIDEO_ONLY,
+    // Wasn't optimized because keyframe distance is too big.
+    FAIL_FOR_KEYFRAME_DISTANCE,
+    // Wasn't optimized because is being played remotely.
+    FAIL_FOR_REMOTE,
+    // Wasn't optimized because is a streaming video.
+    FAIL_FOR_STREAMING,
+
+    // Must be the last item and set to the previous item's value.
+    RESULT_MAX = FAIL_FOR_STREAMING
+  };
+
+  // Reports the result of each background optimization check.
+  // Figures the right bucket based on whether the video has audio or not.
+  void ReportBackgroundOptimizationResult(
+      BackgroundOptimizationResult result) const;
+
   blink::WebLocalFrame* frame_;
 
   // The playback state last reported to |delegate_|, to avoid setting duplicate