Register system Pepper Flash plugin if no packaged Pepper plugin is found.

chrome/chrome_common.gypi

 # Copyright (c) 2013 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': {
     # File lists shared with GN build.
     'chrome_common_sources': [
       'common/all_messages.h',
       'common/attrition_experiments.h',
@@ skipping 398 matching lines @@
             '<(DEPTH)/components/nacl.gyp:nacl_common',
           ],
         }],
         ['enable_plugins==1', {
           'dependencies': [
             '<(DEPTH)/third_party/adobe/flash/flash_player.gyp:flapper_version_h',
           ],
           'sources': [
             'common/pepper_flash.cc',
             'common/pepper_flash.h',
+            'common/ppapi_utils.cc',
+            'common/ppapi_utils.h',
           ],
         }],
         ['enable_plugins==1 and enable_extensions==1', {
           'sources': [
             'common/pepper_permission_util.cc',
             'common/pepper_permission_util.h',
           ],
         }],
         ['enable_basic_printing==1 or enable_print_preview==1', {
           'dependencies': [
@@ skipping 240 matching lines @@
         'common/safe_browsing/csd.proto'
       ],
       'variables': {
         'proto_in_dir': 'common/safe_browsing',
         'proto_out_dir': 'chrome/common/safe_browsing',
       },
       'includes': [ '../build/protoc.gypi' ],
     },
   ],
 }