MacViews a11y: Get simple field editing plaing nice with VoiceOver.

ui/accessibility/platform/ax_platform_node_mac.mm

 // Copyright 2014 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.
 
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 203 matching lines @@
       // TODO(patricialor): Add more events.
   };
 
   EventMap event_map;
   for (size_t i = 0; i < arraysize(events); ++i)
     event_map[events[i].value] = events[i].nativeValue;
   return event_map;
 }
 
 void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
-  NSAccessibilityPostNotification(
-      target, [AXPlatformNodeCocoa nativeNotificationFromAXEvent:event_type]);
+  if (event_type == ui::AX_EVENT_VALUE_CHANGED) {
+    // VoiceOver stopped responding correctly to
+    // NSAccessibilityValueChangedNotification for text fields in 10.11. But
+    // notifying the element as destroyed and subsequently focused elicits good
+    // behavior from VoiceOver for simple text fields.
+    NSAccessibilityPostNotification(
+        target, NSAccessibilityUIElementDestroyedNotification);
+    NSAccessibilityPostNotification(
+        target, NSAccessibilityFocusedUIElementChangedNotification);
+  } else {
+    NSAccessibilityPostNotification(
+        target, [AXPlatformNodeCocoa nativeNotificationFromAXEvent:event_type]);
+  }
 }
 
 }  // namespace
 
 @interface AXPlatformNodeCocoa ()
 // Helper function for string attributes that don't require extra processing.
 - (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute;
 // Returns AXValue, or nil if AXValue isn't an NSString.
 - (NSString*)getAXValueAsString;
 @end
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   }
   NotifyMacEvent(native_node_, event_type);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui