Allow for building content_shell from within WebKit

content/content_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.
 
 {
   'dependencies': [
     'browser/debugger/devtools_resources.gyp:devtools_resources',
     'browser/speech/proto/speech_proto.gyp:speech_proto',
     '../base/base.gyp:base_static',
     '../crypto/crypto.gyp:crypto',
     '../net/net.gyp:http_server',
     '../net/net.gyp:net',
     '../ppapi/ppapi_internal.gyp:ppapi_proxy',
     '../skia/skia.gyp:skia',
     '../third_party/flac/flac.gyp:libflac',
     '../third_party/speex/speex.gyp:libspeex',
-    '../third_party/WebKit/Source/WebKit/chromium/WebKit.gyp:webkit',
+    '<(webkit_src_dir)/Source/WebKit/chromium/WebKit.gyp:webkit',
     '../third_party/zlib/zlib.gyp:zlib',
     '../ui/surface/surface.gyp:surface',
     '../ui/ui.gyp:ui',
     '../ui/ui.gyp:ui_resources',
     '../webkit/support/webkit_support.gyp:dom_storage',
     '../webkit/support/webkit_support.gyp:webkit_resources',
     '../webkit/support/webkit_support.gyp:webkit_strings',
   ],
   'include_dirs': [
     '..',
@@ skipping 918 matching lines @@
       ],
     }],
     ['input_speech==0', {
       'sources/': [
         ['exclude', '^browser/speech/'],
       ],
     }],
   ],
 }