[ToolbarActionViewController] Update return type of GetId().

chrome/browser/ui/views/toolbar/browser_actions_container.h

 // Copyright 2013 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_VIEWS_TOOLBAR_BROWSER_ACTIONS_CONTAINER_H_
 #define CHROME_BROWSER_UI_VIEWS_TOOLBAR_BROWSER_ACTIONS_CONTAINER_H_
 
 #include "base/observer_list.h"
 #include "chrome/browser/extensions/extension_keybinding_registry.h"
 #include "chrome/browser/ui/toolbar/toolbar_actions_bar.h"
@@ skipping 150 matching lines @@
   ToolbarActionView* GetToolbarActionViewAt(int index) {
     return toolbar_action_views_[index];
   }
 
   // Whether we are performing resize animation on the container.
   bool animating() const {
     return resize_animation_ && resize_animation_->is_animating();
   }
 
   // Returns the ID of the action represented by the view at |index|.
-  const std::string& GetIdAt(size_t index) const;
+  std::string GetIdAt(size_t index) const;
 
   // Returns the ToolbarActionView* associated with the given |extension|, or
   // NULL if none exists.
   ToolbarActionView* GetViewForId(const std::string& id);
 
   // Update the views to reflect the state of the toolbar actions.
   void RefreshToolbarActionViews();
 
   // Returns how many actions are currently visible. If the intent is to find
   // how many are visible once the container finishes animation, see
@@ skipping 166 matching lines @@
 
   // The extension bubble that is actively showing, if any.
   views::BubbleDelegateView* active_bubble_;
 
   base::ObserverList<BrowserActionsContainerObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserActionsContainer);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TOOLBAR_BROWSER_ACTIONS_CONTAINER_H_