Less strict checked state changes and introduce disabled state for content

content/browser/accessibility/browser_accessibility_cocoa.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <execinfo.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
@@ skipping 850 matching lines @@
   if (browserAccessibility_->GetHtmlAttribute("aria-dropeffect", &dropEffects))
     return base::SysUTF8ToNSString(dropEffects);
 
   return nil;
 }
 
 - (NSNumber*)enabled {
   if (![self instanceActive])
     return nil;
   return [NSNumber numberWithBool:
-      GetState(browserAccessibility_, ui::AX_STATE_ENABLED)];
+      !GetState(browserAccessibility_, ui::AX_STATE_DISABLED)];
 }
 
 // Returns a text marker that points to the last character in the document that
 // can be selected with VoiceOver.
 - (id)endTextMarker {
   if (![self instanceActive])
     return nil;
 
   const BrowserAccessibility* root =
       browserAccessibility_->manager()->GetRoot();
@@ skipping 1833 matching lines @@
   if (![self instanceActive])
     return [super hash];
   return browserAccessibility_->GetId();
 }
 
 - (BOOL)accessibilityShouldUseUniqueId {
   return YES;
 }
 
 @end