AcceleratorProvider: Make GetAcceleratorForCommandId const.

chrome/test/base/menu_model_test.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_TEST_BASE_MENU_MODEL_TEST_H_
 #define CHROME_TEST_BASE_MENU_MODEL_TEST_H_
 
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/models/simple_menu_model.h"
 
 // A mix-in class to be used in addition to something that derrives from
 // testing::Test to provide some extra functionality for testing menu models.
 class MenuModelTest {
  public:
   MenuModelTest() {}
   virtual ~MenuModelTest() {}
 
  protected:
   // A menu delegate that counts the number of times certain things are called
   // to make sure things are hooked up properly.
   class Delegate : public ui::SimpleMenuModel::Delegate,
                    public ui::AcceleratorProvider {
    public:
     Delegate() : execute_count_(0), enable_count_(0) {}
 
     bool IsCommandIdChecked(int command_id) const override;
     bool IsCommandIdEnabled(int command_id) const override;
-    bool GetAcceleratorForCommandId(int command_id,
-                                    ui::Accelerator* accelerator) override;
+    bool GetAcceleratorForCommandId(
+        int command_id,
+        ui::Accelerator* accelerator) const override;
     void ExecuteCommand(int command_id, int event_flags) override;
 
     int execute_count_;
     mutable int enable_count_;
   };
 
   // Recursively checks the enabled state and executes a command on every item
   // that's not a separator or a submenu parent item. The returned count should
   // match the number of times the delegate is called to ensure every item
   // works.
   void CountEnabledExecutable(ui::MenuModel* model, int* count);
 
   Delegate delegate_;
 };
 
 #endif  // CHROME_TEST_BASE_MENU_MODEL_TEST_H_