Changing SessionService to have a BaseSessionService, not being one.

chrome/browser/sessions/session_backend.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_backend.h"
 
 #include <limits>
 
 #include "base/files/file.h"
 #include "base/files/file_util.h"
@@ skipping 222 matching lines @@
   // Need to check current_session_file_ again, ResetFile may fail.
   if (current_session_file_.get() && current_session_file_->IsValid() &&
       !AppendCommandsToFile(current_session_file_.get(), commands)) {
     current_session_file_.reset(NULL);
   }
   empty_file_ = false;
 }
 
 void SessionBackend::ReadLastSessionCommands(
     const base::CancelableTaskTracker::IsCanceledCallback& is_canceled,
-    const BaseSessionService::InternalGetCommandsCallback& callback) {
+    const BaseSessionService::GetCommandsCallback& callback) {
   if (is_canceled.Run())
     return;
 
   Init();
 
   ScopedVector<SessionCommand> commands;
   ReadLastSessionCommandsImpl(&commands);
   callback.Run(commands.Pass());
 }
 
@@ skipping 139 matching lines @@
 }
 
 base::FilePath SessionBackend::GetCurrentSessionPath() {
   base::FilePath path = path_to_dir_;
   if (type_ == BaseSessionService::TAB_RESTORE)
     path = path.AppendASCII(kCurrentTabSessionFileName);
   else
     path = path.AppendASCII(kCurrentSessionFileName);
   return path;
 }