Add an accessibility alert for incorrect use of some accelerators.

ash/default_accessibility_delegate.cc

 // Copyright 2013 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 "ash/default_accessibility_delegate.h"
 
 #include <limits>
 
 namespace ash {
 namespace internal {
 
 DefaultAccessibilityDelegate::DefaultAccessibilityDelegate()
     : spoken_feedback_enabled_(false),
       high_contrast_enabled_(false),
       screen_magnifier_enabled_(false),
       screen_magnifier_type_(kDefaultMagnifierType),
       large_cursor_enabled_(false),
-      autoclick_enabled_(false) {
+      autoclick_enabled_(false),
+      accessibility_alert_(A11Y_ALERT_NONE) {
 }
 
 DefaultAccessibilityDelegate::~DefaultAccessibilityDelegate() {}
 
 bool DefaultAccessibilityDelegate::IsSpokenFeedbackEnabled() const {
   return spoken_feedback_enabled_;
 }
 
 void DefaultAccessibilityDelegate::ToggleHighContrast() {
   high_contrast_enabled_ = !high_contrast_enabled_;
@@ skipping 47 matching lines @@
   spoken_feedback_enabled_ = !spoken_feedback_enabled_;
 }
 
 void DefaultAccessibilityDelegate::SaveScreenMagnifierScale(double scale) {
 }
 
 double DefaultAccessibilityDelegate::GetSavedScreenMagnifierScale() {
   return std::numeric_limits<double>::min();
 }
 
+void DefaultAccessibilityDelegate::TriggerAccessibilityAlert(
+    AccessibilityAlert alert) {
+  accessibility_alert_ = alert;
+}
+
+AccessibilityAlert DefaultAccessibilityDelegate::GetLastAccessibilityAlert() {
+  return accessibility_alert_;
+}
+
 }  // namespace internal
 }  // namespace ash