app_shell: Add experimental shellPrivate extension API

extensions/browser/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 
 # GYP version: extensions/extensions.gyp:extensions_browser
 source_set("browser") {
   sources = [
@@ skipping 134 matching lines @@
       "api/runtime/runtime_api.cc",
       "api/runtime/runtime_api.h",
       "api/runtime/runtime_api_delegate.cc",
       "api/runtime/runtime_api_delegate.h",
       "api/serial/serial_api.cc",
       "api/serial/serial_api.h",
       "api/serial/serial_connection.cc",
       "api/serial/serial_connection.h",
       "api/serial/serial_event_dispatcher.cc",
       "api/serial/serial_event_dispatcher.h",
+      "api/shell_private/shell_private_api.cc",
+      "api/shell_private/shell_private_api.h",
       "api/socket/socket.cc",
       "api/socket/socket.h",
       "api/socket/socket_api.cc",
       "api/socket/socket_api.h",
       "api/socket/tcp_socket.cc",
       "api/socket/tcp_socket.h",
       "api/socket/tls_socket.cc",
       "api/socket/tls_socket.h",
       "api/socket/udp_socket.cc",
       "api/socket/udp_socket.h",
@@ skipping 306 matching lines @@
       ]
     }
   }
 
   if (is_win) {
     cflags = [
       "/wd4267", # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     ]
   }
 }