Move plugin messages to content.

content/content_common.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.
 
 {
   'targets': [
     {
       'target_name': 'content_common',
       'type': '<(library)',
       'dependencies': [
         '../ipc/ipc.gyp:ipc',
         '../third_party/icu/icu.gyp:icuuc',
+        '../third_party/npapi/npapi.gyp:npapi',
         '../third_party/WebKit/Source/WebKit/chromium/WebKit.gyp:webkit',
         '../webkit/support/webkit_support.gyp:appcache',
         '../webkit/support/webkit_support.gyp:blob',
         '../webkit/support/webkit_support.gyp:database',
         '../webkit/support/webkit_support.gyp:fileapi',
       ],
       'include_dirs': [
         '..',
       ],
       'sources': [
@@ skipping 63 matching lines @@
         'common/notification_observer.h',
         'common/notification_registrar.cc',
         'common/notification_registrar.h',
         'common/notification_service.cc',
         'common/notification_service.h',
         'common/notification_source.cc',
         'common/notification_source.h',
         'common/notification_type.h',
         'common/p2p_messages.h',
         'common/p2p_sockets.h',
+        'common/plugin_messages.h',
         'common/property_bag.cc',
         'common/property_bag.h',
         'common/resource_dispatcher.cc',
         'common/resource_dispatcher.h',
         'common/resource_messages.h',
         'common/resource_response.cc',
         'common/resource_response.h',
         'common/sandbox_init_wrapper.h',
         'common/sandbox_init_wrapper_linux.cc',
         'common/sandbox_init_wrapper_mac.cc',
@@ skipping 14 matching lines @@
         'common/worker_messages.h',
       ],
       'conditions': [
         ['OS=="win"', {
           'msvs_guid': '062E9260-304A-4657-A74C-0D3AA1A0A0A4',
         }],
       ],
     },
   ],
 }