Initial support for native accessibility in ARC

components/exo/wm_helper.cc

 // Copyright 2016 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 "components/exo/wm_helper.h"
 
 #include "base/memory/ptr_util.h"
 
 namespace exo {
 namespace {
@@ skipping 21 matching lines @@
 
 void WMHelper::AddActivationObserver(ActivationObserver* observer) {
   activation_observers_.AddObserver(observer);
 }
 
 void WMHelper::RemoveActivationObserver(ActivationObserver* observer) {
   activation_observers_.RemoveObserver(observer);
 }
 
 void WMHelper::AddFocusObserver(FocusObserver* observer) {
-  focus_observers_.AddObserver(observer);
+  if (!focus_observers_.HasObserver(observer))
+    focus_observers_.AddObserver(observer);
 }
 
 void WMHelper::RemoveFocusObserver(FocusObserver* observer) {
   focus_observers_.RemoveObserver(observer);
 }
 
 void WMHelper::AddCursorObserver(CursorObserver* observer) {
   cursor_observers_.AddObserver(observer);
 }
 
@@ skipping 62 matching lines @@
   for (AccessibilityObserver& observer : accessibility_observers_)
     observer.OnAccessibilityModeChanged();
 }
 
 void WMHelper::NotifyKeyboardDeviceConfigurationChanged() {
   for (InputDeviceEventObserver& observer : input_device_event_observers_)
     observer.OnKeyboardDeviceConfigurationChanged();
 }
 
 }  // namespace exo