Replace --ppapi-keep-alive-throttle command line switch with IPC parameter.

ppapi/ppapi_shared.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.
 
 {
   'target_defaults': {
     'variables': {
       'ppapi_shared_target': 0,
     },
     'target_conditions': [
@@ skipping 28 matching lines @@
           'shared_impl/host_resource.h',
           'shared_impl/id_assignment.cc',
           'shared_impl/id_assignment.h',
           'shared_impl/media_stream_buffer.h',
           'shared_impl/media_stream_buffer_manager.cc',
           'shared_impl/media_stream_buffer_manager.h',
           'shared_impl/media_stream_video_track_shared.h',
           'shared_impl/media_stream_video_track_shared.cc',
           'shared_impl/platform_file.cc',
           'shared_impl/platform_file.h',
+          'shared_impl/ppapi_constants.h',
           'shared_impl/ppapi_globals.cc',
           'shared_impl/ppapi_globals.h',
           'shared_impl/ppapi_nacl_plugin_args.cc',
           'shared_impl/ppapi_nacl_plugin_args.h',
           'shared_impl/ppapi_permissions.cc',
           'shared_impl/ppapi_permissions.h',
           'shared_impl/ppapi_preferences.cc',
           'shared_impl/ppapi_preferences.h',
           'shared_impl/ppapi_switches.cc',
           'shared_impl/ppapi_switches.h',
@@ skipping 287 matching lines @@
               'thunk/ppb_tcp_socket_private_thunk.cc',
               'thunk/ppb_udp_socket_private_thunk.cc',
               'thunk/ppb_x509_certificate_private_thunk.cc',
             ],
           }],
         ],
       }],
     ],
   },
 }