Add hack so VoiceOver speaks updates to injected live regions.

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>
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <map>
 
@@ skipping 1012 matching lines @@
   BrowserAccessibilityManagerMac* manager =
       static_cast<BrowserAccessibilityManagerMac*>(
           browserAccessibility_->manager());
   return [manager->parent_view() window];
 }
 
 - (NSString*)methodNameForAttribute:(NSString*)attribute {
   return [attributeToMethodNameMap objectForKey:attribute];
 }
 
+- (void)swapChildren:(base::scoped_nsobject<NSMutableArray>*)other {
+  children_.swap(*other);
+}
+
 // Returns the accessibility value for the given attribute.  If the value isn't
 // supported this will return nil.
 - (id)accessibilityAttributeValue:(NSString*)attribute {
   if (!browserAccessibility_)
     return nil;
 
   SEL selector =
       NSSelectorFromString([self methodNameForAttribute:attribute]);
   if (selector)
     return [self performSelector:selector];
@@ skipping 524 matching lines @@
     return [super hash];
   return browserAccessibility_->GetId();
 }
 
 - (BOOL)accessibilityShouldUseUniqueId {
   return YES;
 }
 
 @end