Enable the VariationsService on official builds when --variations-service-url is provided.

chrome/browser/metrics/variations/variations_service.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/browser/metrics/variations/variations_service.h"
 
 #include <set>
 
 #include "base/base64.h"
 #include "base/build_time.h"
@@ skipping 141 matching lines @@
   DCHECK(create_trials_from_seed_called_);
 
   // Perform the first fetch.
   FetchVariationsSeed();
 
   // Repeat this periodically.
   timer_.Start(FROM_HERE, base::TimeDelta::FromHours(kSeedFetchPeriodHours),
                this, &VariationsService::FetchVariationsSeed);
 }
 
+void VariationsService::SetCreateTrialsFromSeedCalledForTesting(bool called) {
+  create_trials_from_seed_called_ = called;
+}
+
 // static
 void VariationsService::RegisterPrefs(PrefServiceSimple* prefs) {
   prefs->RegisterStringPref(prefs::kVariationsSeed, std::string());
   prefs->RegisterInt64Pref(prefs::kVariationsSeedDate,
                            base::Time().ToInternalValue());
 }
 
-void VariationsService::SetCreateTrialsFromSeedCalledForTesting(bool called) {
-  create_trials_from_seed_called_ = called;
+// static
+VariationsService* VariationsService::Create() {
+// See http://crbug.com/168224

[Alexei Svitkine (slow), 2013/01/03 20:40:42]

Indent 2. Make the comment mention android, otherwise its not clear what its
referring to.

[SteveT, 2013/01/03 20:46:39]

Done.

+#if defined(GOOGLE_CHROME_BUILD) && !defined(OS_ANDROID)
+  // Unless the URL was provided, unsupported builds should return NULL to
+  // indicate that the service should not be used.
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kVariationsServerURL))
+    return NULL;
+#endif
+  return new VariationsService;
 }
 
 void VariationsService::DoActualFetch() {
   pending_seed_request_.reset(net::URLFetcher::Create(
       variations_server_url_, net::URLFetcher::GET, this));
   pending_seed_request_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                                       net::LOAD_DO_NOT_SAVE_COOKIES);
   pending_seed_request_->SetRequestContext(
       g_browser_process->system_request_context());
   pending_seed_request_->SetMaxRetriesOn5xx(kMaxRetrySeedFetch);
@@ skipping 330 matching lines @@
                                       variation_id);
     }
   }
 
   trial->SetForced();
   if (IsStudyExpired(study, reference_date))
     trial->Disable();
 }
 
 }  // namespace chrome_variations