Add hack so VoiceOver speaks updates to injected live regions.

content/browser/accessibility/browser_accessibility_cocoa.h

Index: content/browser/accessibility/browser_accessibility_cocoa.h
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.h b/content/browser/accessibility/browser_accessibility_cocoa.h
index 8f38eaaa170c6fffb740a06f13056679149d5a30..5fc708f867bdebf2a9e892579d6fa3dfbf1ad31c 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.h
+++ b/content/browser/accessibility/browser_accessibility_cocoa.h
@@ -48,6 +48,9 @@
 // Return the method name for the given attribute. For testing only.
 - (NSString*)methodNameForAttribute:(NSString*)attribute;
 
+// Swap the children array with the given scoped_nsobject.
+- (void)swapChildren:(base::scoped_nsobject<NSMutableArray>*)other;
+
 // Internally-used method.
 @property(nonatomic, readonly) NSPoint origin;