AcceleratorProvider: Make GetAcceleratorForCommandId const.

ash/shelf/shelf_view_unittest.cc

 // Copyright (c) 2012 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/shelf/shelf_view.h"
 
 #include <algorithm>
 #include <memory>
 #include <utility>
 #include <vector>
@@ skipping 2034 matching lines @@
 
   // ShelfMenuModel:
   bool IsCommandActive(int command_id) const override { return false; }
 
   // ui::SimpleMenuModel::Delegate:
   bool IsCommandIdChecked(int command_id) const override { return false; }
   bool IsCommandIdEnabled(int command_id) const override {
     return command_id != 0;
   }
   bool GetAcceleratorForCommandId(int command_id,
-                                  ui::Accelerator* accelerator) override {
+                                  ui::Accelerator* accelerator) const override {
     return false;
   }
   void ExecuteCommand(int command_id, int event_flags) override {}
 
   DISALLOW_COPY_AND_ASSIGN(TestShelfMenuModel);
 };
 
 // A ShelfItemDelegate that returns a menu for the shelf item.
 class ListMenuShelfItemDelegate : public TestShelfItemDelegate {
  public:
@@ skipping 525 matching lines @@
   test_api_->CloseMenu();
   EXPECT_EQ(views::InkDropState::HIDDEN,
             browser_button_ink_drop_->GetTargetInkDropState());
   EXPECT_THAT(browser_button_ink_drop_->GetAndResetRequestedStates(),
               ElementsAre(views::InkDropState::ACTIVATED,
                           views::InkDropState::DEACTIVATED));
 }
 
 }  // namespace test
 }  // namespace ash