Correct UseCounter::FormNameAccessForImageElement.

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

Index: third_party/WebKit/Source/core/html/HTMLFormElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLFormElement.cpp b/third_party/WebKit/Source/core/html/HTMLFormElement.cpp
index a552cb1b96bcde7af7115b992003a059aef77c43..6cd1c1e4f59c4b9dd881a8e98f8bbc972120c3f2 100644
--- a/third_party/WebKit/Source/core/html/HTMLFormElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLFormElement.cpp
@@ -836,12 +836,14 @@ void HTMLFormElement::anonymousNamedGetter(const AtomicString& name, RadioNodeLi
     getNamedElements(name, elements);
     ASSERT(!elements.isEmpty());
 
+    bool onlyMatchImg = !elements.isEmpty() && isHTMLImageElement(*elements.first());
+    if (onlyMatchImg)

[sof, 2015/11/13 08:21:48]

Hmm, what if the <img> element doesn't appear first and/or there are multiple
with that id/name?

[tkent, 2015/11/13 08:28:25]

I'd like to count only cases where this function returns an IMG element or
RadioNodeList with IMG elements. The current code is enough because
RadioNodeList with onlyMatchImg=false won't include IMG elements.

[sof, 2015/11/13 08:33:10]

Yes, this looks correct & precise as-is -- step 2 from
https://html.spec.whatwg.org/multipage/forms.html#dom-form-nameditem will only
return IMGs and never a list with IMGs mixed in. lgtm.

+        UseCounter::count(document(), UseCounter::FormNameAccessForImageElement);
     if (elements.size() == 1) {
         returnValue.setElement(elements.at(0));
         return;
     }
 
-    bool onlyMatchImg = !elements.isEmpty() && isHTMLImageElement(*elements.first());
     returnValue.setRadioNodeList(radioNodeList(name, onlyMatchImg));
 }