Add two UseCounters for form.imageName and form.elements.imageName.

third_party/WebKit/Source/core/html/HTMLFormControlsCollection.cpp

Index: third_party/WebKit/Source/core/html/HTMLFormControlsCollection.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLFormControlsCollection.cpp b/third_party/WebKit/Source/core/html/HTMLFormControlsCollection.cpp
index e7ced66a415c5138e1f42d662c686cb7ec3cf94d..bbdceba87fcbd018e9c2b8664e8cb8703e9da901 100644
--- a/third_party/WebKit/Source/core/html/HTMLFormControlsCollection.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLFormControlsCollection.cpp
@@ -202,10 +202,14 @@ void HTMLFormControlsCollection::namedGetter(const AtomicString& name, RadioNode
         return;
 
     if (namedItems.size() == 1) {
+        if (isHTMLImageElement(*namedItems[0]))
+            UseCounter::count(document(), UseCounter::FormControlsCollectionNameAccessForImageElement);
         returnValue.setElement(namedItems.at(0));
         return;
     }
 
+    // This path never returns a RadioNodeList for <img> because
+    // onlyMatchingImgElements flag is false by default.
     returnValue.setRadioNodeList(ownerNode().radioNodeList(name));
 }