Add use counters for lots of DOM APIs.

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

Index: third_party/WebKit/Source/core/clipboard/DataTransferItemList.idl
diff --git a/third_party/WebKit/Source/core/clipboard/DataTransferItemList.idl b/third_party/WebKit/Source/core/clipboard/DataTransferItemList.idl
index a38c0578d1027f1cba0250e46eb39f2486129e91..c2b0d6416e3c7c6a062c02249f31b2ae0ada4a03 100644
--- a/third_party/WebKit/Source/core/clipboard/DataTransferItemList.idl
+++ b/third_party/WebKit/Source/core/clipboard/DataTransferItemList.idl
@@ -31,10 +31,10 @@
 // https://html.spec.whatwg.org/#the-datatransferitemlist-interface
 
 interface DataTransferItemList {
-    readonly attribute unsigned long length;
-    [ImplementedAs=item] getter DataTransferItem (unsigned long index);
-    [RaisesException] DataTransferItem? add(DOMString data, DOMString type);
-    DataTransferItem? add(File file);
-    [RaisesException, ImplementedAs=deleteItem] void remove(unsigned long index);
-    void clear();
+    [MeasureAs=DataTransferItemListAPI] readonly attribute unsigned long length;
+    [ImplementedAs=item, MeasureAs=DataTransferItemListAPI] getter DataTransferItem (unsigned long index);
+    [RaisesException, MeasureAs=DataTransferItemListAPI] DataTransferItem? add(DOMString data, DOMString type);
+    [MeasureAs=DataTransferItemListAPI] DataTransferItem? add(File file);
+    [RaisesException, ImplementedAs=deleteItem, MeasureAs=DataTransferItemListAPI] void remove(unsigned long index);
+    [MeasureAs=DataTransferItemListAPI] void clear();
 };