Add use counters for global user prompt methods

Source/core/frame/Window.idl

Index: Source/core/frame/Window.idl
diff --git a/Source/core/frame/Window.idl b/Source/core/frame/Window.idl
index 1ff5e495f0edaad211cde7d8bb0d398672b1495d..28d8f0bf4b391b09422c690f8430997ac69673ff 100644
--- a/Source/core/frame/Window.idl
+++ b/Source/core/frame/Window.idl
@@ -72,11 +72,11 @@
     [RuntimeEnabled=ApplicationCache, LogActivity=GetterOnly] readonly attribute ApplicationCache applicationCache;
 
     // user prompts
-    void alert();
-    void alert(DOMString message);
-    boolean confirm(optional DOMString message = "");
-    DOMString? prompt(optional DOMString message = "", optional DOMString defaultValue = "");
-    void print();
+    [Measure] void alert();
+    [Measure] void alert(DOMString message);
+    [Measure] boolean confirm(optional DOMString message = "");
+    [Measure] DOMString? prompt(optional DOMString message = "", optional DOMString defaultValue = "");
+    [Measure] void print();
 
     [MeasureAs=UnprefixedRequestAnimationFrame] long requestAnimationFrame(FrameRequestCallback callback);
     void cancelAnimationFrame(long handle);