Remove task.h and finish base::Bind() migration.

chrome/browser/ui/gtk/back_forward_button_gtk.h

 // Copyright (c) 2011 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_GTK_BACK_FORWARD_BUTTON_GTK_H_
 #define CHROME_BROWSER_UI_GTK_BACK_FORWARD_BUTTON_GTK_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "base/task.h"
 #include "chrome/browser/ui/gtk/custom_button.h"
 #include "chrome/browser/ui/gtk/menu_gtk.h"
 #include "ui/base/gtk/gtk_signal.h"
 
 class BackForwardMenuModel;
 class Browser;
 
 typedef struct _GtkWidget GtkWidget;
 
 // When clicked, these buttons will navigate forward or backward. When
@@ skipping 42 matching lines @@
 
   // The y position of the last mouse down event.
   int y_position_of_last_press_;
 
   base::WeakPtrFactory<BackForwardButtonGtk> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BackForwardButtonGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_BACK_FORWARD_BUTTON_GTK_H_