Blur immediately if an attribute change made an element unfocasable.

third_party/WebKit/Source/core/html/HTMLAnchorElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 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 84 matching lines @@
 
   void parseAttribute(const QualifiedName&,
                       const AtomicString&,
                       const AtomicString&) override;
   bool supportsFocus() const override;
   bool matchesEnabledPseudoClass() const override;
 
  private:
   class NavigationHintSender;
 
+  void attributeChanged(const QualifiedName&,
+                        const AtomicString&,
+                        const AtomicString&,
+                        AttributeModificationReason) override;
   bool shouldHaveFocusAppearance() const final;
   void dispatchFocusEvent(Element* oldFocusedElement,
                           WebFocusType,
                           InputDeviceCapabilities* sourceCapabilities) override;
   void dispatchBlurEvent(Element* newFocusedElement,
                          WebFocusType,
                          InputDeviceCapabilities* sourceCapabilities) override;
   bool isMouseFocusable() const override;
   bool isKeyboardFocusable() const override;
   void defaultEventHandler(Event*) final;
@@ skipping 23 matching lines @@
 }
 
 // Functions shared with the other anchor elements (i.e., SVG).
 
 bool isEnterKeyKeydownEvent(Event*);
 bool isLinkClick(Event*);
 
 }  // namespace blink
 
 #endif  // HTMLAnchorElement_h