[Autoplay] Add histogram metrics for cross-origin autoplay muted experiment

third_party/WebKit/Source/core/html/AutoplayUmaHelper.h

Index: third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
diff --git a/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h b/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
index 88bd8dfe08d0d87140ec435ec2262cddd0d0efcc..5d836bf38d9db3a5e5018600c50beaa34a99ffac 100644
--- a/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
+++ b/third_party/WebKit/Source/core/html/AutoplayUmaHelper.h
@@ -41,9 +41,12 @@ enum AutoplayBlockedReason {
 };
 
 enum class CrossOriginAutoplayResult {
-  AutoplayAllowed,
-  AutoplayBlocked,
-  PlayedWithGesture,
+  AutoplayAllowed = 0,
+  AutoplayBlocked = 1,
+  PlayedWithGesture = 2,
+  UserPaused = 3,
+  // Keep at the end.
+  NumberOfResults = 4,
 };
 
 class Document;
@@ -130,9 +133,6 @@ class CORE_EXPORT AutoplayUmaHelper : public EventListener,
 
   std::set<CrossOriginAutoplayResult> m_recordedCrossOriginAutoplayResults;
 
-  // Whether the UMA helper has recorded user pausing a cross-origin video.
-  bool m_hasRecordedUserPausedAutoplayingCrossOriginVideo;
-
   // The observer is used to observer an autoplaying muted video changing it's
   // visibility, which is used for offscreen duration UMA.  The UMA is pending
   // for recording as long as this observer is non-null.