Enable building with configuration_policy==1 on ios.

components/policy/core/common/cloud/policy_builder.cc

 // 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.
 
 #include "components/policy/core/common/cloud/policy_builder.h"
 
 #include <vector>
 
 #include "base/stl_util.h"
 #include "components/policy/core/common/cloud/cloud_policy_constants.h"
@@ skipping 210 matching lines @@
 
 template<>
 TypedPolicyBuilder<em::CloudPolicySettings>::TypedPolicyBuilder()
     : payload_(new em::CloudPolicySettings()) {
   policy_data().set_policy_type(dm_protocol::kChromeUserPolicyType);
 }
 
 // Have the instantiation compiled into the module.
 template class TypedPolicyBuilder<em::CloudPolicySettings>;
 
-#if !defined(OS_ANDROID)
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
 template<>
 TypedPolicyBuilder<em::ExternalPolicyData>::TypedPolicyBuilder()
     : payload_(new em::ExternalPolicyData()) {
   policy_data().set_policy_type(dm_protocol::kChromeExtensionPolicyType);
 }
 
 template class TypedPolicyBuilder<em::ExternalPolicyData>;
 #endif
 
 }  // namespace policy