Wire up windowless plugins. Mostly Mac related, some cross

app/app.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'includes': [
     '../build/common.gypi',
@@ skipping 50 matching lines @@
         'animation.h',
         'app_paths.h',
         'app_paths.cc',
         'app_switches.h',
         'app_switches.cc',
         'drag_drop_types.cc',
         'drag_drop_types.h',
         'gfx/canvas.cc',
         'gfx/canvas.h',
         'gfx/canvas_linux.cc',
+        'gfx/canvas_mac.mm',
         'gfx/canvas_win.cc',
         'gfx/font.h',
         'gfx/font_gtk.cc',
         'gfx/font_mac.mm',
         'gfx/font_skia.cc',
         'gfx/font_win.cc',
         'gfx/color_utils.cc',
         'gfx/color_utils.h',
         'gfx/favicon_size.h',
         'gfx/icon_util.cc',
@@ skipping 186 matching lines @@
         ],
       },
       'conditions': [
         ['OS=="win"', {
           'dependencies': ['../build/win/system.gyp:cygwin'],
         }],
       ],
     },    
   ],
 }