[Sync] Fix namespaces for the sync_sessions component.

components/sync/driver/fake_sync_service.cc

 // Copyright 2015 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/sync/driver/fake_sync_service.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
 #include "components/sync/core/base_transaction.h"
 #include "components/sync/core/user_share.h"
@@ skipping 80 matching lines @@
 }
 
 bool FakeSyncService::HasUnrecoverableError() const {
   return false;
 }
 
 bool FakeSyncService::IsBackendInitialized() const {
   return false;
 }
 
-OpenTabsUIDelegate* FakeSyncService::GetOpenTabsUIDelegate() {
+sync_sessions::OpenTabsUIDelegate* FakeSyncService::GetOpenTabsUIDelegate() {
   return nullptr;
 }
 
 bool FakeSyncService::IsPassphraseRequiredForDecryption() const {
   return false;
 }
 
 base::Time FakeSyncService::GetExplicitPassphraseTime() const {
   return base::Time();
 }
@@ skipping 95 matching lines @@
     syncer::TypeDebugInfoObserver* observer) {}
 
 base::WeakPtr<syncer::JsController> FakeSyncService::GetJsController() {
   return base::WeakPtr<syncer::JsController>();
 }
 
 void FakeSyncService::GetAllNodes(
     const base::Callback<void(std::unique_ptr<base::ListValue>)>& callback) {}
 
 }  // namespace sync_driver