Add accessible names to the launcher buttons

ash/launcher/launcher_button_host.h

Index: ash/launcher/launcher_button_host.h
diff --git a/ash/launcher/launcher_button_host.h b/ash/launcher/launcher_button_host.h
index 1cc94614a423ca9596d02b80390247e612d7a082..2c8138552f9a3df64b806ee93168c22eb039554c 100644
--- a/ash/launcher/launcher_button_host.h
+++ b/ash/launcher/launcher_button_host.h
@@ -6,6 +6,8 @@
 #define ASH_LAUNCHER_LAUNCHER_BUTTON_HOST_H_
 #pragma once
 
+#include "base/string16.h"
+
 namespace views {
 class MouseEvent;
 class View;
@@ -33,6 +35,9 @@ class LauncherButtonHost {
   // Invoked when the mouse exits the item.
   virtual void MouseExitedButton(views::View* view) = 0;
 
+  // Invoked to get the accessible name of the item.
+  virtual string16 GetAccessibleName(views::View* view) = 0;
+
  protected:
   virtual ~LauncherButtonHost() {}
 };