revert r53268:

chrome/browser/gtk/tabs/tab_strip_gtk.h

 // Copyright (c) 2009 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_GTK_TABS_TAB_STRIP_GTK_H_
 #define CHROME_BROWSER_GTK_TABS_TAB_STRIP_GTK_H_
 
 #include <gtk/gtk.h>
 #include <vector>
 
@@ skipping 35 matching lines @@
 
   TabStripModel* model() const { return model_; }
 
   BrowserWindowGtk* window() const { return window_; }
 
   GtkWidget* widget() const { return tabstrip_.get(); }
 
   // Returns true if there is an active drag session.
   bool IsDragSessionActive() const { return drag_controller_.get() != NULL; }
 
-  // Cancels the current drag session, if any.
-  void CancelActiveDragSession();
-
   // Sets the bounds of the tabs.
   void Layout();
 
   // Queues a draw for the tabstrip widget.
   void SchedulePaint();
 
   // Sets the bounds of the tabstrip.
   void SetBounds(const gfx::Rect& bounds);
 
   // Returns the bounds of the tabstrip.
@@ skipping 385 matching lines @@
   // ResizeLayoutTabsNow method.
   ScopedRunnableMethodFactory<TabStripGtk> resize_layout_factory_;
 
   // True if the tabstrip has already been added as a MessageLoop observer.
   bool added_as_message_loop_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TabStripGtk);
 };
 
 #endif  // CHROME_BROWSER_GTK_TABS_TAB_STRIP_GTK_H_