Add use counters for recently launched canvas features

third_party/WebKit/Source/core/html/HTMLCanvasElement.idl

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.idl
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.idl b/third_party/WebKit/Source/core/html/HTMLCanvasElement.idl
index f2aa7983cc2b4642a326da23e8f81382a0a3666c..a636a41e7f00022b085e383aaaf25c7648b191ce 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.idl
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.idl
@@ -38,7 +38,7 @@ interface HTMLCanvasElement : HTMLElement
     // Note: The arguments argument is variadic in the spec, but not here as
     // only one extra argument is actually used.
     // FIXME: type should not have a default value.
-    [RaisesException] DOMString toDataURL(optional DOMString type = null, optional any arguments);
+    [MeasureAs=CanvasToDataURL, RaisesException] DOMString toDataURL(optional DOMString type = null, optional any arguments);
 
-    [RaisesException] void toBlob(BlobCallback _callback, optional DOMString type = null, optional any arguments);
+    [MeasureAs=CanvasToBlob, RaisesException] void toBlob(BlobCallback _callback, optional DOMString type = null, optional any arguments);
 };