Add PanelBrowserTitlebarGtk for panels on GTK.

chrome/chrome_browser.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 3055 matching lines @@
         'browser/ui/panels/docked_panel_strip.h',
         'browser/ui/panels/native_panel.h',
         'browser/ui/panels/panel.cc',
         'browser/ui/panels/panel.h',
         'browser/ui/panels/panel_bounds_animation.cc',
         'browser/ui/panels/panel_bounds_animation.h',
         'browser/ui/panels/panel_browser_frame_view.cc',
         'browser/ui/panels/panel_browser_frame_view.h',
         'browser/ui/panels/panel_browser_view.cc',
         'browser/ui/panels/panel_browser_view.h',
+        'browser/ui/panels/panel_browser_titlebar_gtk.cc',
+        'browser/ui/panels/panel_browser_titlebar_gtk.h',
         'browser/ui/panels/panel_browser_window_cocoa.h',
         'browser/ui/panels/panel_browser_window_cocoa.mm',
         'browser/ui/panels/panel_browser_window_gtk.cc',
         'browser/ui/panels/panel_browser_window_gtk.h',
         'browser/ui/panels/panel_constants.h',
         'browser/ui/panels/panel_drag_controller.cc',
         'browser/ui/panels/panel_drag_controller.h',
         'browser/ui/panels/panel_drag_gtk.cc',
         'browser/ui/panels/panel_drag_gtk.h',
         'browser/ui/panels/panel_resize_controller.cc',
@@ skipping 2119 matching lines @@
       'type': 'static_library',
       'sources': [ 'browser/chromeos/gdata/gdata.proto' ],
       'variables': {
         'proto_in_dir': 'browser/chromeos/gdata',
         'proto_out_dir': 'chrome/browser/chromeos/gdata',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }