Add UseCounters for prefixed HTMLVideoElement APIs

Source/core/html/HTMLVideoElement.cpp

Index: Source/core/html/HTMLVideoElement.cpp
diff --git a/Source/core/html/HTMLVideoElement.cpp b/Source/core/html/HTMLVideoElement.cpp
index 5bea9764c204f789445916db0b3b813f14f7ee40..d63869f33bce8f4d5f6c88e8aa0b974c70799693 100644
--- a/Source/core/html/HTMLVideoElement.cpp
+++ b/Source/core/html/HTMLVideoElement.cpp
@@ -219,8 +219,10 @@ bool HTMLVideoElement::hasAvailableVideoFrame() const
     return player()->hasVideo() && player()->readyState() >= MediaPlayer::HaveCurrentData;
 }
 
-void HTMLVideoElement::webkitEnterFullscreen(ExceptionState& es)
+void HTMLVideoElement::webkitEnterFullscreen(ExceptionState& es, UseCounter::Feature feature)
 {
+    UseCounter::count(document(), feature);
+
     if (isFullscreen())
         return;
 
@@ -234,19 +236,22 @@ void HTMLVideoElement::webkitEnterFullscreen(ExceptionState& es)
     enterFullscreen();
 }
 
-void HTMLVideoElement::webkitExitFullscreen()
+void HTMLVideoElement::webkitExitFullscreen(UseCounter::Feature feature)
 {
+    UseCounter::count(document(), feature);
     if (isFullscreen())
         exitFullscreen();
 }
 
 bool HTMLVideoElement::webkitSupportsFullscreen()
 {
+    UseCounter::count(document(), UseCounter::PrefixedVideoSupportsFullscreen);
     return supportsFullscreen();
 }
 
 bool HTMLVideoElement::webkitDisplayingFullscreen()
 {
+    UseCounter::count(document(), UseCounter::PrefixedVideoDisplayingFullscreen);
     return isFullscreen();
 }
 
@@ -259,6 +264,8 @@ void HTMLVideoElement::didMoveToNewDocument(Document& oldDocument)
 
 unsigned HTMLVideoElement::webkitDecodedFrameCount() const
 {
+    UseCounter::count(document(), UseCounter::PrefixedVideoDecodedFrameCount);
+
     if (!player())
         return 0;
 
@@ -267,6 +274,8 @@ unsigned HTMLVideoElement::webkitDecodedFrameCount() const
 
 unsigned HTMLVideoElement::webkitDroppedFrameCount() const
 {
+    UseCounter::count(document(), UseCounter::PrefixedVideoDroppedFrameCount);
+
     if (!player())
         return 0;