Identity extension API impl: Split constants into their own file

chrome/browser/extensions/api/identity/identity_remove_cached_auth_token_function.cc

 // Copyright 2017 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 "chrome/browser/extensions/api/identity/identity_remove_cached_auth_token_function.h"
 
 #include "chrome/browser/extensions/api/identity/identity_api.h"
+#include "chrome/browser/extensions/api/identity/identity_constants.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/extensions/api/identity.h"
 
 namespace extensions {
 
 namespace identity = api::identity;
 
 IdentityRemoveCachedAuthTokenFunction::IdentityRemoveCachedAuthTokenFunction() {
 }
 
 IdentityRemoveCachedAuthTokenFunction::
     ~IdentityRemoveCachedAuthTokenFunction() {}
 
 ExtensionFunction::ResponseAction IdentityRemoveCachedAuthTokenFunction::Run() {
   if (Profile::FromBrowserContext(browser_context())->IsOffTheRecord())
     return RespondNow(Error(identity_constants::kOffTheRecord));
 
   std::unique_ptr<identity::RemoveCachedAuthToken::Params> params(
       identity::RemoveCachedAuthToken::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
   IdentityAPI::GetFactoryInstance()
       ->Get(browser_context())
       ->EraseCachedToken(extension()->id(), params->details.token);
   return RespondNow(NoArguments());
 }
 
 }  // namespace extensions