Disable sync for Lightspeed experimentation.

chrome/browser/sync/profile_sync_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/sync/profile_sync_service.h"
 
 #include <cstddef>
 #include <map>
 #include <vector>
 
@@ skipping 57 matching lines @@
 #include "components/signin/core/browser/about_signin_internals.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/signin/core/browser/signin_metrics.h"
 #include "components/sync_driver/change_processor.h"
 #include "components/sync_driver/data_type_controller.h"
 #include "components/sync_driver/device_info.h"
 #include "components/sync_driver/pref_names.h"
 #include "components/sync_driver/system_encryptor.h"
 #include "components/sync_driver/user_selectable_sync_type.h"
+#include "components/variations/variations_associated_data.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 #include "net/cookies/cookie_monster.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "sync/api/sync_error.h"
 #include "sync/internal_api/public/configure_reason.h"
 #include "sync/internal_api/public/http_bridge_network_resources.h"
 #include "sync/internal_api/public/network_resources.h"
@@ skipping 2360 matching lines @@
 base::WeakPtr<syncer::JsController> ProfileSyncService::GetJsController() {
   return sync_js_controller_.AsWeakPtr();
 }
 
 void ProfileSyncService::SyncEvent(SyncEventCodes code) {
   UMA_HISTOGRAM_ENUMERATION("Sync.EventCodes", code, MAX_SYNC_EVENT_CODE);
 }
 
 // static
 bool ProfileSyncService::IsSyncEnabled() {
+  // Disable sync experimentally to measure impact on startup time.
+  // TODO(mlerman): Remove this after the experiment. crbug.com/454788

[Alexei Svitkine (slow), 2015/02/19 22:04:08]

Nit: Add this comment above the other variations check too.

[Mike Lerman, 2015/02/20 16:38:02]

Done.

+  if (!variations::GetVariationParamValue("LightSpeed", "DisableSync").empty())
+      return false;

[Bernhard Bauer, 2015/02/18 21:12:44]

Nit: indent two spaces less.

[Mike Lerman, 2015/02/20 16:38:01]

Done.

+
   // We have switches::kEnableSync just in case we need to change back to
   // sync-disabled-by-default on a platform.
   return !base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableSync);
 }
 
 bool ProfileSyncService::IsManaged() const {
   return sync_prefs_.IsManaged() || sync_disabled_by_admin_;
 }
 
@@ skipping 276 matching lines @@
 
 base::MessageLoop* ProfileSyncService::GetSyncLoopForTest() const {
   if (sync_thread_) {
     return sync_thread_->message_loop();
   } else if (backend_) {
     return backend_->GetSyncLoopForTesting();
   } else {
     return NULL;
   }
 }