Remove form control related virtual methods from Element

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index e3199112cca649bf8ae7e40a0ba871602fad2a2f..ff5e580bb70eaf891bee1f518b0ea4f4fbf39d2d 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -3363,8 +3363,11 @@ bool Document::setFocusedElement(PassRefPtr<Element> prpNewFocusedElement, Focus
         oldFocusedElement->setFocus(false);
 
         // Dispatch a change event for text fields or textareas that have been edited
-        if (oldFocusedElement->wasChangedSinceLastFormControlChangeEvent())
-            oldFocusedElement->dispatchFormControlChangeEvent();
+        if (oldFocusedElement->isFormControlElement()) {

[tkent, 2014/01/30 01:38:50]

I don't like this change.
It increased virtual calls, and the function needs to know the special
requirement of HTMLFormControlElement.

Alternative idea is to move this code into
HTMLTextFormControlElement::setFocus().

[Inactive, 2014/01/30 01:57:22]

Did it really increase virtual calls? Sure isFormControlElement() is a new
virtual call but wasChangedSinceLastFormControlChangeEvent() is no longer one.
So it looks like it evens out.

I do agree with your second point though. The HTMLFormControlElement special
handling is now more explicit. Overriding Node::setFocus(bool) in
HTMLFormControlElement and moving the code there does sound like a better idea.
It seems setFocus() is only called from this method.

+            HTMLFormControlElement* formControlElement = toHTMLFormControlElement(oldFocusedElement);
+            if (formControlElement->wasChangedSinceLastFormControlChangeEvent())
+                formControlElement->dispatchFormControlChangeEvent();
+        }
 
         // Dispatch the blur event and let the node do any other blur related activities (important for text fields)
         // If page lost focus, blur event will have already been dispatched