Add an accessibility alert for incorrect use of some accelerators.

chrome/browser/ui/ash/chrome_shell_delegate_views.cc

Index: chrome/browser/ui/ash/chrome_shell_delegate_views.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate_views.cc b/chrome/browser/ui/ash/chrome_shell_delegate_views.cc
index 440ed0a829885a45ac56a9c21c4cbcb6ee6488cc..3e12d751025560effe4d0776d9b1bd0a55024c63 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate_views.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate_views.cc
@@ -10,6 +10,7 @@
 #include "ash/system/tray/default_system_tray_delegate.h"
 #include "ash/wm/window_util.h"
 #include "base/command_line.h"
+#include "chrome/browser/accessibility/accessibility_events.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -122,6 +123,14 @@ class EmptyAccessibilityDelegate : public ash::AccessibilityDelegate {
   virtual void SilenceSpokenFeedback() const OVERRIDE {
   }
 
+  virtual void TriggerAccessibilityAlert(
+      ash::AccessibilityAlert alert) OVERRIDE {
+  }
+
+  virtual ash::AccessibilityAlert GetLastAccessibilityAlert() OVERRIDE {
+    return ash::A11Y_ALERT_NONE;
+  }
+
  private:
   DISALLOW_COPY_AND_ASSIGN(EmptyAccessibilityDelegate);
 };