Add use counters for lots of DOM APIs.

third_party/WebKit/Source/core/clipboard/DataTransfer.idl

Index: third_party/WebKit/Source/core/clipboard/DataTransfer.idl
diff --git a/third_party/WebKit/Source/core/clipboard/DataTransfer.idl b/third_party/WebKit/Source/core/clipboard/DataTransfer.idl
index 7f5d90aa20f086be24905610dbf0a47a3a4b4f15..2fce45f1135b22f3b20f06b1a06c77645ac39c3b 100644
--- a/third_party/WebKit/Source/core/clipboard/DataTransfer.idl
+++ b/third_party/WebKit/Source/core/clipboard/DataTransfer.idl
@@ -29,19 +29,19 @@
 // https://html.spec.whatwg.org/#the-datatransfer-interface
 
 interface DataTransfer {
-    attribute DOMString dropEffect;
-    attribute DOMString effectAllowed;
+    [Measure] attribute DOMString dropEffect;
+    [Measure] attribute DOMString effectAllowed;
 
-    [SameObject] readonly attribute DataTransferItemList items;
+    [SameObject, Measure] readonly attribute DataTransferItemList items;
 
-    void setDragImage(Element image, long x, long y);
+    [Measure] void setDragImage(Element image, long x, long y);
 
     /* old interface */
     // TODO(foolip): Switch to FrozenArray<DOMString> when the spec is fixed:
     // https://github.com/whatwg/html/issues/11
-    [SameObject] readonly attribute DOMString[] types;
-    DOMString getData(DOMString format);
-    void setData(DOMString format, DOMString data);
-    void clearData(optional DOMString format);
-    [SameObject] readonly attribute FileList files;
+    [SameObject, Measure] readonly attribute DOMString[] types;
+    [Measure] DOMString getData(DOMString format);
+    [Measure] void setData(DOMString format, DOMString data);
+    [Measure] void clearData(optional DOMString format);
+    [SameObject, Measure] readonly attribute FileList files;
 };