Changing CloudPrintURLFetcher instantiation to be more testable

chrome/service/cloud_print/cloud_print_url_fetcher.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 "chrome/service/cloud_print/cloud_print_url_fetcher.h"
 
 #include "base/stringprintf.h"
 #include "base/values.h"
 #include "chrome/common/cloud_print/cloud_print_constants.h"
 #include "chrome/common/cloud_print/cloud_print_helpers.h"
 #include "chrome/service/cloud_print/cloud_print_helpers.h"
 #include "chrome/service/cloud_print/cloud_print_token_store.h"
 #include "chrome/service/net/service_url_request_context.h"
 #include "chrome/service/service_process.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_status.h"
 
 namespace cloud_print {
 
+static CloudPrintURLFetcherFactory* g_factory = NULL;
+
+// static
+CloudPrintURLFetcher* CloudPrintURLFetcher::Create() {
+  CloudPrintURLFetcherFactory* factory = CloudPrintURLFetcher::factory();
+  return factory ? factory->CreateCloudPrintURLFetcher() :
+      new CloudPrintURLFetcher;
+}
+
+// static
+CloudPrintURLFetcherFactory* CloudPrintURLFetcher::factory() {
+  return g_factory;
+}
+
+// static
+void CloudPrintURLFetcher::set_factory(CloudPrintURLFetcherFactory* factory) {
+  g_factory = factory;
+}
+
 CloudPrintURLFetcher::ResponseAction
 CloudPrintURLFetcher::Delegate::HandleRawResponse(
     const net::URLFetcher* source,
     const GURL& url,
     const net::URLRequestStatus& status,
     int response_code,
     const net::ResponseCookies& cookies,
     const std::string& data) {
   return CONTINUE_PROCESSING;
 }
@@ skipping 175 matching lines @@
   ServiceURLRequestContextGetter* getter =
       g_service_process->GetServiceURLRequestContextGetter();
   // Now set up the user agent for cloudprint.
   std::string user_agent = getter->user_agent();
   base::StringAppendF(&user_agent, " %s", kCloudPrintUserAgent);
   getter->set_user_agent(user_agent);
   return getter;
 }
 
 }  // namespace cloud_print