Moved the following IPC messages used by the chrome NPAPI plugin installer out of content

chrome/chrome_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.
 
 {
   'target_defaults': {
     'variables': {
       'chrome_common_target': 0,
     },
     'target_conditions': [
@@ skipping 119 matching lines @@
         'common/automation_messages.cc',
         'common/automation_messages.h',
         'common/automation_messages_internal.h',
         'common/badge_util.cc',
         'common/badge_util.h',
         'common/bzip2_error_handler.cc',
         'common/chrome_content_client.cc',
         'common/chrome_content_client.h',
         'common/chrome_content_plugin_client.cc',
         'common/chrome_content_plugin_client.h',
+        'common/chrome_plugin_messages.h',
         'common/cloud_print/cloud_print_proxy_info.cc',
         'common/cloud_print/cloud_print_proxy_info.h',
         'common/common_api.h',
         'common/common_message_generator.cc',
         'common/common_message_generator.h',
         'common/common_param_traits.cc',
         'common/common_param_traits.h',
         'common/custom_handlers/protocol_handler.cc',
         'common/custom_handlers/protocol_handler.h',
         'common/default_plugin.cc',
@@ skipping 340 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }