Delete the GTK+ port of Chrome.

ui/surface/surface.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
 
   'target_defaults': {
@@ skipping 19 matching lines @@
         '<(DEPTH)/ui/gfx/gfx.gyp:gfx',
         '<(DEPTH)/ui/gfx/gfx.gyp:gfx_geometry',
         '<(DEPTH)/ui/gl/gl.gyp:gl',
       ],
       'sources': [
         'accelerated_surface_mac.cc',
         'accelerated_surface_mac.h',
         'surface_export.h',
         'transport_dib.h',
         'transport_dib.cc',
-        'transport_dib_gtk.cc',
         'transport_dib_posix.cc',
         'transport_dib_win.cc',
       ],
       'defines': [
         'SURFACE_IMPLEMENTATION',
       ],
     },
   ],
 }