Make it possible to focus on 0-size form controls and anchors.

Source/core/html/HTMLFormControlElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 99 matching lines @@
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual void requiredAttributeChanged();
     virtual void disabledAttributeChanged();
     virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual void didMoveToNewDocument(Document* oldDocument) OVERRIDE;
 
     virtual bool supportsFocus() const OVERRIDE;
-    virtual bool rendererIsFocusable() const OVERRIDE;
     virtual bool isKeyboardFocusable() const OVERRIDE;
     virtual bool shouldShowFocusRingOnMouseFocus() const;
     virtual bool shouldHaveFocusAppearance() const OVERRIDE;
     virtual void dispatchFocusEvent(Element* oldFocusedElement, FocusDirection) OVERRIDE;
     virtual void dispatchBlurEvent(Element* newFocusedElement) OVERRIDE;
     virtual void willCallDefaultEventHandler(const Event&) OVERRIDE;
 
     virtual void didRecalcStyle(StyleChange) OVERRIDE;
 
     // This must be called any time the result of willValidate() has changed.
@@ skipping 48 matching lines @@
 
 inline HTMLFormControlElement* toHTMLFormControlElement(FormAssociatedElement* control)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!control || control->isFormControlElement());
     return static_cast<HTMLFormControlElement*>(control);
 }
 
 } // namespace
 
 #endif