sync: avoid creating a HistoryModelWorker unless it is needed.

chrome/browser/sync/test_profile_sync_service.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_BROWSER_SYNC_TEST_PROFILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_TEST_PROFILE_SYNC_SERVICE_H_
 #pragma once
 
 #include <string>
 
@@ skipping 149 matching lines @@
     if (synchronous_init_) {
       // The SyncBackend posts a task to the current loop when
       // initialization completes.
       MessageLoop::current()->Run();
     }
   }
 
   static void SetDefaultExpectationsForWorkerCreation(ProfileMock* profile) {
     EXPECT_CALL(*profile, GetPasswordStore(testing::_)).
         WillOnce(testing::Return((PasswordStore*)NULL));
+  }
+
+  static void SetHistoryServiceExpectations(ProfileMock* profile) {
     EXPECT_CALL(*profile, GetHistoryService(testing::_)).
         WillOnce(testing::Return((HistoryService*)NULL));
   }
 
  private:
   Task* initial_condition_setup_task_;
   bool set_initial_sync_ended_on_init_;
   bool synchronous_init_;
 };
 
@@ skipping 76 matching lines @@
   bool synchronous_sync_configuration_;
   bool set_expect_resume_expectations_;
   int num_expected_resumes_;
   int num_expected_pauses_;
 
   scoped_ptr<Task> initial_condition_setup_task_;
   bool set_initial_sync_ended_on_init_;
 };
 
 #endif  // CHROME_BROWSER_SYNC_TEST_PROFILE_SYNC_SERVICE_H_