[Blink>Media] Record MediaSession API interface usage metrics

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 dc8e309a9a14643706d5b8a582c9ea1789307010..a11ba242313c7591bd55181cacb194dc027c2581 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.h
+++ b/third_party/WebKit/Source/core/frame/UseCounter.h
@@ -1439,6 +1439,11 @@ class CORE_EXPORT UseCounter {
     HTMLTableCellElementColspanGreaterThan8190 = 1785,
     SelectionAddRangeIntersect = 1786,
     PostMessageFromInsecureToSecureToplevel = 1787,
+    V8MediaSession_Metadata_AttributeGetter = 1788,
+    V8MediaSession_Metadata_AttributeSetter = 1789,
+    V8MediaSession_PlaybackState_AttributeGetter = 1790,
+    V8MediaSession_PlaybackState_AttributeSetter = 1791,
+    V8MediaSession_SetActionHandler_Method = 1792,
 
     // Add new features immediately above this line. Don't change assigned
     // numbers of any item, and don't reuse removed slots.