Add IOS_BUNDLE_ID_PREFIX to Clean Skeleton target.

ios/clean/chrome/app/BUILD.gn

 # Copyright 2015 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/ios/rules.gni")
 import("//build/config/mac/base_rules.gni")
 import("//build/mac/tweak_info_plist.gni")
 import("//ios/build/chrome_build.gni")
 import("//ios/public/provider/chrome/browser/build_config.gni")
 
@@ skipping 28 matching lines @@
 
   bundle_deps = [ "//ios/chrome/app/resources" ]
 
   extra_substitutions = [
     "CHROMIUM_BUNDLE_ID=$chromium_bundle_id",
     "CHROMIUM_SHORT_NAME=$chromium_short_name",
     "CHROMIUM_URL_SCHEME_1=$url_unsecure_scheme",
     "CHROMIUM_URL_SCHEME_2=$url_secure_scheme",
     "CHROMIUM_URL_SCHEME_3=$url_x_callback_scheme",
     "CHROMIUM_URL_SCHEME_4=$url_channel_scheme",
+    "IOS_BUNDLE_ID_PREFIX=$ios_app_bundle_id_prefix",
   ]
 
   if (ios_encryption_export_compliance_code != "") {
     extra_substitutions += [ "ENCRYPTION_EXPORT_COMPLIANCE_CODE=" +
                              ios_encryption_export_compliance_code ]
   }
 }
 
 source_set("main") {
   sources = [
@@ skipping 38 matching lines @@
     "app_delegate.mm",
   ]
 
   configs += [ "//build/config/compiler:enable_arc" ]
 
   deps = [
     ":application_state",
     "//ios/clean/chrome/app/steps",
   ]
 }