Make the gyp files more cross-platform across the Unices

ui/gfx/surface/surface.gyp

 # 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.
 
 {
   'target_defaults': {
     'sources/': [
       ['exclude', '/(cocoa|gtk|win)/'],
       ['exclude', '_(cocoa|gtk|linux|mac|posix|win|x)\\.(cc|mm?)$'],
       ['exclude', '/(gtk|win|x11)_[^/]*\\.cc$'],
     ],
     'conditions': [
-      ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {'sources/': [
-        ['include', '/gtk/'],
-        ['include', '_(gtk|linux|posix|skia|x)\\.cc$'],
-        ['include', '/(gtk|x11)_[^/]*\\.cc$'],
-      ]}],
+      ['toolkit_uses_gtk == 1', {
+        'sources/': [
+          ['include', '/gtk/'],
+          ['include', '_(gtk|linux|posix|skia|x)\\.cc$'],
+          ['include', '/(gtk|x11)_[^/]*\\.cc$'],
+        ],
+      }],
       ['OS=="mac"', {'sources/': [
         ['include', '/cocoa/'],
         ['include', '_(cocoa|mac|posix)\\.(cc|mm?)$'],
       ]}, { # else: OS != "mac"
         'sources/': [
           ['exclude', '\\.mm?$'],
         ],
       }],
       ['OS=="win"',
         {'sources/': [
@@ skipping 20 matching lines @@
         'io_surface_support_mac.cc',
         'io_surface_support_mac.h',
         'transport_dib.h',
         'transport_dib_linux.cc',
         'transport_dib_mac.cc',
         'transport_dib_win.cc',
       ],
     },
   ],
 }