AcceleratorProvider: Make GetAcceleratorForCommandId const.

ui/views/controls/menu/menu_runner_cocoa_unittest.mm

 // Copyright 2014 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.
 
 #import "ui/views/controls/menu/menu_runner_impl_cocoa.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 17 matching lines @@
   }
 
  private:
   class Delegate : public ui::SimpleMenuModel::Delegate {
    public:
     explicit Delegate(TestModel* model) : model_(model) {}
     bool IsCommandIdChecked(int command_id) const override {
       return command_id == model_->checked_command_;
     }
     bool IsCommandIdEnabled(int command_id) const override { return true; }
-    bool GetAcceleratorForCommandId(int command_id,
-                                    ui::Accelerator* accelerator) override {
+    bool GetAcceleratorForCommandId(
+        int command_id,
+        ui::Accelerator* accelerator) const override {
       return false;
     }
     void ExecuteCommand(int command_id, int event_flags) override {}
 
     void MenuWillShow(SimpleMenuModel* source) override {
       model_->menu_open_callback_.Run();
     }
 
    private:
     TestModel* model_;
@@ skipping 207 matching lines @@
   // In RTL, Cocoa messes up the positioning unless the anchor rectangle is
   // offset to the right of the view. The offset for the checkmark is also
   // skipped, to give a better match to native behavior.
   base::i18n::SetICUDefaultLocale("he");
   RunMenuAt(anchor_rect);
   EXPECT_EQ(combobox_rect.right(), last_anchor_frame_.origin.x);
 }
 
 }  // namespace test
 }  // namespace views