Add PanelBrowserTitlebarGtk for panels on GTK.

chrome/browser/ui/gtk/browser_window_gtk.h

 // Copyright (c) 2012 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_BROWSER_WINDOW_GTK_H_
 #define CHROME_BROWSER_UI_GTK_BROWSER_WINDOW_GTK_H_
 #pragma once
 
 #include <gtk/gtk.h>
 
@@ skipping 245 matching lines @@
   // redraw when it should.
   void QueueToolbarRedraw();
 
   // Get the position where the infobar arrow should be anchored in
   // |relative_to| coordinates. This is the middle of the omnibox location icon.
   int GetXPositionOfLocationIcon(GtkWidget* relative_to);
 
  protected:
   virtual void DestroyBrowser() OVERRIDE;
 
+  // Returns an instance of |BrowserTitlebar| to be used for this window.
+  virtual BrowserTitlebar* CreateBrowserTitlebar();
+
   // Checks to see if the mouse pointer at |x|, |y| is over the border of the
   // custom frame (a spot that should trigger a window resize). Returns true if
   // it should and sets |edge|.
   virtual bool GetWindowEdge(int x, int y, GdkWindowEdge* edge);
 
   virtual bool HandleTitleBarLeftMousePress(GdkEventButton* event,
                                             guint32 last_click_time,
                                             gfx::Point last_click_position);
 
   // Returns true if handled.
@@ skipping 284 matching lines @@
   scoped_ptr<FullscreenExitBubbleGtk> fullscreen_exit_bubble_;
 
   FullscreenExitBubbleType fullscreen_exit_bubble_type_;
 
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserWindowGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_BROWSER_WINDOW_GTK_H_