Changing SessionService to have a BaseSessionService, not being one.

chrome/browser/sessions/session_service_test_helper.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/sessions/session_service_test_helper.h"
 
 #include "base/memory/scoped_vector.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/sessions/session_backend.h"
 #include "chrome/browser/sessions/session_service.h"
@@ skipping 42 matching lines @@
   service()->force_browser_not_alive_with_no_windows_ =
       force_browser_not_alive_with_no_windows;
 }
 
 // Be sure and null out service to force closing the file.
 void SessionServiceTestHelper::ReadWindows(
     std::vector<SessionWindow*>* windows,
     SessionID::id_type* active_window_id) {
   Time last_time;
   ScopedVector<SessionCommand> read_commands;
-  backend()->ReadLastSessionCommandsImpl(&read_commands);
+  service()->GetBaseSessionServiceForTest()->backend()->
+      ReadLastSessionCommandsImpl(&read_commands);
   RestoreSessionFromCommands(read_commands, windows, active_window_id);
   service()->RemoveUnusedRestoreWindows(windows);
 }
 
 void SessionServiceTestHelper::AssertTabEquals(const SessionID& window_id,
                                                const SessionID& tab_id,
                                                int visual_index,
                                                int nav_index,
                                                size_t nav_count,
                                                const SessionTab& session_tab) {
@@ skipping 22 matching lines @@
 }
 
 void SessionServiceTestHelper::AssertSingleWindowWithSingleTab(
     const std::vector<SessionWindow*>& windows,
     size_t nav_count) {
   ASSERT_EQ(1U, windows.size());
   EXPECT_EQ(1U, windows[0]->tabs.size());
   EXPECT_EQ(nav_count, windows[0]->tabs[0]->navigations.size());
 }
 
-SessionBackend* SessionServiceTestHelper::backend() {
-  return service_->backend();
-}
-
 void SessionServiceTestHelper::SetService(SessionService* service) {
   service_.reset(service);
   // Execute IO tasks posted by the SessionService.
   content::RunAllBlockingPoolTasksUntilIdle();
 }
 
 void SessionServiceTestHelper::RunTaskOnBackendThread(
     const tracked_objects::Location& from_here,
     const base::Closure& task) {
-  service_->RunTaskOnBackendThread(from_here, task);
+  service_->GetBaseSessionServiceForTest()->RunTaskOnBackendThread(from_here,
+                                                                   task);
 }