Restore proxy_id after generation new Service State file.

cloud_print/service/win/chrome_launcher.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 "cloud_print/service/win/chrome_launcher.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 67 matching lines @@
 }
 
 GURL GetCloudPrintServiceEnableURLWithSignin(const std::string& proxy_id) {
   GURL url(GaiaUrls::GetInstance()->service_login_url());
   url = net::AppendQueryParameter(url, "service", "cloudprint");
   url = net::AppendQueryParameter(url, "sarp", "1");
   return net::AppendQueryParameter(
       url, "continue", GetCloudPrintServiceEnableURL(proxy_id).spec());
 }
 
-std::string UpdateServiceState(const std::string& json) {
+std::string UpdateServiceState(const std::string& json,
+                               const std::string& proxy_id) {
   std::string result;
 
   scoped_ptr<base::Value> service_state(base::JSONReader::Read(json));
   base::DictionaryValue* dictionary = NULL;
   if (!service_state->GetAsDictionary(&dictionary) || !dictionary) {
     return result;
   }
 
   bool enabled = false;
   if (!dictionary->GetBoolean(prefs::kCloudPrintProxyEnabled, &enabled) ||
       !enabled) {
     return result;
   }
 
   // Remove everything except kCloudPrintRoot.
   base::Value* cloud_print_root = NULL;
   dictionary->Remove(prefs::kCloudPrintRoot, &cloud_print_root);
   dictionary->Clear();
   dictionary->Set(prefs::kCloudPrintRoot, cloud_print_root);
 
   dictionary->SetBoolean(prefs::kCloudPrintXmppPingEnabled, true);
-
-  base::JSONWriter::Write(dictionary, &result);
-
+  dictionary->SetString(prefs::kCloudPrintProxyId, proxy_id);
+  base::JSONWriter::WriteWithOptions(dictionary,
+                                     base::JSONWriter::OPTIONS_PRETTY_PRINT,
+                                     &result);
   return result;
 }
 
 void DeleteAutorunKeys(const base::FilePath& user_data_dir) {
   base::win::RegKey key(HKEY_CURRENT_USER, kAutoRunKeyPath, KEY_SET_VALUE);
   if (!key.Valid())
     return;
   std::vector<string16> to_delete;
 
   base::FilePath abs_user_data_dir = user_data_dir;
@@ skipping 172 matching lines @@
     LOG(ERROR) << "Chrome launch failed.";
     return result;
   }
 
   std::string json;
   if (!file_util::ReadFileToString(
           temp_user_data.path().Append(chrome::kServiceStateFileName), &json)) {
     return result;
   }
 
-  return UpdateServiceState(json);
+  return UpdateServiceState(json, proxy_id);
 }