chrome: Cleanup class/struct forward declarations

chrome/browser/ui/toolbar/toolbar_actions_bar_delegate.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_BAR_DELEGATE_H_
 #define CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_BAR_DELEGATE_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "ui/gfx/animation/tween.h"
 #include "ui/gfx/geometry/size.h"
 
 class ToolbarActionViewController;
 class ToolbarActionsBarBubbleDelegate;
 
-namespace extensions {
-class ExtensionMessageBubbleController;
-}
-
 // The delegate class (which, in production, represents the view) of the
 // ToolbarActionsBar.
 class ToolbarActionsBarDelegate {
  public:
   enum GetWidthTime {
     GET_WIDTH_CURRENT,          // Returns the current width.
     GET_WIDTH_AFTER_ANIMATION,  // Returns the width after a running animation.
   };
 
   virtual ~ToolbarActionsBarDelegate() {}
@@ skipping 26 matching lines @@
   // Stops the current animation (width remains where it currently is).
   virtual void StopAnimating() = 0;
 
   // Shows the given |bubble|. Must not be called if another bubble is showing
   // or if the toolbar is animating.
   virtual void ShowToolbarActionBubble(
       std::unique_ptr<ToolbarActionsBarBubbleDelegate> bubble) = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_TOOLBAR_ACTIONS_BAR_DELEGATE_H_