Measure usage of MediaStream.prototype.active

third_party/WebKit/Source/core/frame/UseCounter.h

Index: third_party/WebKit/Source/core/frame/UseCounter.h
diff --git a/third_party/WebKit/Source/core/frame/UseCounter.h b/third_party/WebKit/Source/core/frame/UseCounter.h
index d86e35582b006553b1e05b8f6ad599809c6a7f92..751fa1af9a1eb7ec992eaee9c954e91db7253f0a 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.h
+++ b/third_party/WebKit/Source/core/frame/UseCounter.h
@@ -1234,10 +1234,13 @@ public:
         MediaSourceAbortRemove = 1428,
         MediaSourceDurationTruncatingBuffered = 1429,
         AudioContextCrossOriginIframe = 1430,
+        // The above items are available in M53 branch
+
         PointerEventSetCapture = 1431,
         PointerEventDispatch = 1432,
         MIDIMessageEventReceivedTime = 1433,
         SummaryElementWithDisplayBlockAuthorRule = 1434,
+        V8MediaStream_Active_AttributeGetter = 1435,
 
         // Add new features immediately above this line. Don't change assigned
         // numbers of any item, and don't reuse removed slots.