Add hack so VoiceOver speaks updates to injected live regions.

content/browser/accessibility/browser_accessibility_mac.mm

Index: content/browser/accessibility/browser_accessibility_mac.mm
diff --git a/content/browser/accessibility/browser_accessibility_mac.mm b/content/browser/accessibility/browser_accessibility_mac.mm
index 3d13ee8190d39aab3a7f4016bad7ff185bd90067..1d4c2f92a7fc86ad24f2da6674598696a26d4e48 100644
--- a/content/browser/accessibility/browser_accessibility_mac.mm
+++ b/content/browser/accessibility/browser_accessibility_mac.mm
@@ -48,6 +48,21 @@ bool BrowserAccessibilityMac::IsNative() const {
   return true;
 }
 
+void BrowserAccessibilityMac::RecreateNativeObject() {
+  if (!browser_accessibility_cocoa_)
+    return;
+
+  // Preserve the children so that recreating the native object doesn't
+  // end up recreating the whole subtree.
+  base::scoped_nsobject<NSMutableArray> children;
+  [browser_accessibility_cocoa_ swapChildren:&children];
+  [browser_accessibility_cocoa_ detach];
+  [browser_accessibility_cocoa_ release];
+  browser_accessibility_cocoa_ = [[BrowserAccessibilityCocoa alloc]
+      initWithObject:this];
+  [browser_accessibility_cocoa_ swapChildren:&children];
+}
+
 BrowserAccessibilityCocoa* BrowserAccessibility::ToBrowserAccessibilityCocoa() {
   return static_cast<BrowserAccessibilityMac*>(this)->
       native_view();