[ToolbarActionViewController] Update return type of GetId().

chrome/browser/ui/toolbar/test_toolbar_action_view_controller.h

 // Copyright 2015 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_TEST_TOOLBAR_ACTION_VIEW_CONTROLLER_H_
 #define CHROME_BROWSER_UI_TOOLBAR_TEST_TOOLBAR_ACTION_VIEW_CONTROLLER_H_
 
 #include "chrome/browser/ui/toolbar/toolbar_action_view_controller.h"
 
 // A minimalistic and configurable ToolbarActionViewController for use in
 // testing.
 class TestToolbarActionViewController : public ToolbarActionViewController {
  public:
   explicit TestToolbarActionViewController(const std::string& id);
   ~TestToolbarActionViewController() override;
 
   // ToolbarActionViewController:
-  const std::string& GetId() const override;
+  std::string GetId() const override;
   void SetDelegate(ToolbarActionViewDelegate* delegate) override;
   gfx::Image GetIcon(content::WebContents* web_contents,
                      const gfx::Size& size) override;
   base::string16 GetActionName() const override;
   base::string16 GetAccessibleName(content::WebContents* web_contents)
       const override;
   base::string16 GetTooltip(content::WebContents* web_contents)
       const override;
   bool IsEnabled(content::WebContents* web_contents) const override;
   bool WantsToRun(content::WebContents* web_contents) const override;
@@ skipping 41 matching lines @@
   // Whether or not a click on a disabled action should open the context menu.
   bool disabled_click_opens_menu_;
 
   // The number of times the action would have been executed.
   int execute_action_count_;
 
   DISALLOW_COPY_AND_ASSIGN(TestToolbarActionViewController);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_TEST_TOOLBAR_ACTION_VIEW_CONTROLLER_H_