Add use counters for lots of DOM APIs.

third_party/WebKit/Source/core/css/FontFaceSet.idl

Index: third_party/WebKit/Source/core/css/FontFaceSet.idl
diff --git a/third_party/WebKit/Source/core/css/FontFaceSet.idl b/third_party/WebKit/Source/core/css/FontFaceSet.idl
index 573f4bc940c2d41dc93c80cf6ed468fb74ab5dd5..e8328d82e1b868898eb633ea90dee348d744cff1 100644
--- a/third_party/WebKit/Source/core/css/FontFaceSet.idl
+++ b/third_party/WebKit/Source/core/css/FontFaceSet.idl
@@ -40,24 +40,24 @@ enum FontFaceSetLoadStatus { "loading", "loaded" };
     NoInterfaceObject,
 ] interface FontFaceSet : EventTarget {
     setlike<FontFace>;
-    readonly attribute unsigned long size;
+    [MeasureAs=FontFaceSetAPI] readonly attribute unsigned long size;
 
     // events for when loading state changes
-    attribute EventHandler onloading;
-    attribute EventHandler onloadingdone;
-    attribute EventHandler onloadingerror;
+    [MeasureAs=FontFaceSetAPI] attribute EventHandler onloading;
+    [MeasureAs=FontFaceSetAPI] attribute EventHandler onloadingdone;
+    [MeasureAs=FontFaceSetAPI] attribute EventHandler onloadingerror;
 
     // check and start loads if appropriate
     // and fulfill promise when all loads complete
-    [CallWith=ScriptState] Promise<sequence<FontFace>> load(DOMString font, optional DOMString text = " ");
+    [CallWith=ScriptState, MeasureAs=FontFaceSetAPI] Promise<sequence<FontFace>> load(DOMString font, optional DOMString text = " ");
 
     // return whether all fonts in the fontlist are loaded
     // (does not initiate load if not available)
-    [RaisesException] boolean check(DOMString font, optional DOMString text = " ");
+    [RaisesException, MeasureAs=FontFaceSetAPI] boolean check(DOMString font, optional DOMString text = " ");
 
     // async notification that font loading and layout operations are done
-    [CallWith=ScriptState] readonly attribute Promise<FontFaceSet> ready;
+    [CallWith=ScriptState, MeasureAs=FontFaceSetAPI] readonly attribute Promise<FontFaceSet> ready;
 
     // loading state, "loading" while one or more fonts loading, "loaded" otherwise
-    readonly attribute FontFaceSetLoadStatus status;
+    [MeasureAs=FontFaceSetAPI] readonly attribute FontFaceSetLoadStatus status;
 };