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

ui/accessibility/platform/ax_platform_node_mac.mm

Index: ui/accessibility/platform/ax_platform_node_mac.mm
diff --git a/ui/accessibility/platform/ax_platform_node_mac.mm b/ui/accessibility/platform/ax_platform_node_mac.mm
index 240240e6180bc11f40e56de4fa36fdafd9e65b81..b188b66f0aced9e298ecc82e2c6b3c84b7a1849c 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -221,8 +221,19 @@ EventMap BuildEventMap() {
 }
 
 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