Implement CUP signing in UpdateClient.

components/update_client/utils.cc

 // 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.
 
 #include "components/update_client/utils.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <cmath>
 #include <cstring>
@@ skipping 115 matching lines @@
   return request;
 }
 
 scoped_ptr<net::URLFetcher> SendProtocolRequest(
     const GURL& url,
     const std::string& protocol_request,
     net::URLFetcherDelegate* url_fetcher_delegate,
     net::URLRequestContextGetter* url_request_context_getter) {
   scoped_ptr<net::URLFetcher> url_fetcher = net::URLFetcher::Create(
       0, url, net::URLFetcher::POST, url_fetcher_delegate);
+  if (!url_fetcher.get())
+    return url_fetcher;
 
   url_fetcher->SetUploadData("application/xml", protocol_request);
   url_fetcher->SetRequestContext(url_request_context_getter);
   url_fetcher->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                             net::LOAD_DO_NOT_SAVE_COOKIES |
                             net::LOAD_DISABLE_CACHE);
   url_fetcher->SetAutomaticallyRetryOn5xx(false);
   url_fetcher->Start();
 
   return url_fetcher;
@@ skipping 72 matching lines @@
   uint8_t actual_hash[crypto::kSHA256Length] = {0};
   scoped_ptr<crypto::SecureHash> hasher(
       crypto::SecureHash::Create(crypto::SecureHash::SHA256));
   hasher->Update(mmfile.data(), mmfile.length());
   hasher->Finish(actual_hash, sizeof(actual_hash));
 
   return memcmp(actual_hash, &expected_hash[0], sizeof(actual_hash)) == 0;
 }
 
 }  // namespace update_client