[Media Router] Adds a contextual menu item to remove the MR component action.

chrome/browser/ui/toolbar/toolbar_actions_model.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_MODEL_H_
 #define CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_MODEL_H_
 
 #include <stddef.h>
 
 #include "base/compiler_specific.h"
@@ skipping 160 matching lines @@
     return highlighting_for_toolbar_redesign_;
   }
 
   void SetActionVisibility(const std::string& action_id, bool visible);
 
   // ComponentMigrationHelper::ComponentActionDelegate:
   void AddComponentAction(const std::string& action_id) override;
   void RemoveComponentAction(const std::string& action_id) override;
   bool HasComponentAction(const std::string& action_id) const override;
 
+  // Returns this toolbar's component migration helper.  The helper is owned by
+  // |this|.
+  extensions::ComponentMigrationHelper* component_migration_helper() {

[Peter Kasting, 2016/01/26 02:12:35]

Nit: Seems like there's a section above for cheap accessors, I'd imagine this
should be with them.

I doubt the function comment is needed then, since what it says is already
reasonably obvious.

[mark a. foltz, 2016/01/29 00:37:44]

Both done.

+    return component_migration_helper_.get();
+  }
+
   void OnActionToolbarPrefChange();
 
   // Highlights the actions specified by |action_ids|. This will cause
   // the ToolbarModel to only display those actions.
   // Highlighting mode is only entered if there is at least one action to be
   // shown.
   // Returns true if highlighting mode is entered, false otherwise.
   bool HighlightActions(const std::vector<std::string>& action_ids,
                         HighlightType type);
 
@@ skipping 138 matching lines @@
   // For observing change of toolbar order preference by external entity (sync).
   PrefChangeRegistrar pref_change_registrar_;
   base::Closure pref_change_callback_;
 
   base::WeakPtrFactory<ToolbarActionsModel> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ToolbarActionsModel);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_MODEL_H_