Relanding this as the previous attempt failed due to build errors.

content/content_plugin.gypi

 # 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.
 
 {
   'conditions': [
     ['enable_plugins==1', {
       'dependencies': [
         '../skia/skia.gyp:skia',
         '../third_party/npapi/npapi.gyp:npapi',
         '../webkit/support/webkit_support.gyp:glue',
+        '../webkit/support/webkit_support.gyp:plugins',
+        '../webkit/support/webkit_support.gyp:plugins_common',
       ],
       'include_dirs': [
         '<(INTERMEDIATE_DIR)',
       ],
       'sources': [
         # All .cc, .h, .m, and .mm files under plugins except for tests and
         # mocks.
         'plugin/plugin_channel.cc',
         'plugin/plugin_channel.h',
         'plugin/plugin_interpose_util_mac.mm',
@@ skipping 38 matching lines @@
           'link_settings': {
             'libraries': [
               '-lXext',
             ],
           },
         }],
       ],
     }],
   ],
 }