Convert SessionService to use new CancelableTaskTracker

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/file_util.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 226 matching lines @@
   if (current_session_file_.get() && current_session_file_->IsOpen() &&
       !AppendCommandsToFile(current_session_file_.get(), *commands)) {
     current_session_file_.reset(NULL);
   }
   empty_file_ = false;
   STLDeleteElements(commands);
   delete commands;
 }
 
 void SessionBackend::ReadLastSessionCommands(
-    scoped_refptr<BaseSessionService::InternalGetCommandsRequest> request) {
-  if (request->canceled())
+    const CancelableTaskTracker::IsCanceledCallback& is_canceled,
+    const BaseSessionService::InternalGetCommandsCallback& callback) {
+  if (is_canceled.Run())
     return;
+
   Init();
-  ReadLastSessionCommandsImpl(&(request->commands));
-  request->ForwardResult(request->handle(), request);
+
+  ScopedVector<SessionCommand> commands;
+  ReadLastSessionCommandsImpl(&(commands.get()));
+  callback.Run(commands.Pass());
 }
 
 bool SessionBackend::ReadLastSessionCommandsImpl(
     std::vector<SessionCommand*>* commands) {
   Init();
   SessionFileReader file_reader(GetLastSessionPath());
   return file_reader.Read(type_, commands);
 }
 
 void SessionBackend::DeleteLastSession() {
@@ skipping 24 matching lines @@
                                           last_session_path);
   }
 
   if (file_util::PathExists(current_session_path))
     file_util::Delete(current_session_path, false);
 
   // Create and open the file for the current session.
   ResetFile();
 }
 
-void SessionBackend::ReadCurrentSessionCommands(
-    scoped_refptr<BaseSessionService::InternalGetCommandsRequest> request) {
-  if (request->canceled())
-    return;
-  Init();
-  ReadCurrentSessionCommandsImpl(&(request->commands));
-  request->ForwardResult(request->handle(), request);
-}
-
 bool SessionBackend::ReadCurrentSessionCommandsImpl(
     std::vector<SessionCommand*>* commands) {
   Init();
   SessionFileReader file_reader(GetCurrentSessionPath());
   return file_reader.Read(type_, commands);
 }
 
 bool SessionBackend::AppendCommandsToFile(net::FileStream* file,
     const std::vector<SessionCommand*>& commands) {
   for (std::vector<SessionCommand*>::const_iterator i = commands.begin();
@@ skipping 83 matching lines @@
 }
 
 FilePath SessionBackend::GetCurrentSessionPath() {
   FilePath path = path_to_dir_;
   if (type_ == BaseSessionService::TAB_RESTORE)
     path = path.AppendASCII(kCurrentTabSessionFileName);
   else
     path = path.AppendASCII(kCurrentSessionFileName);
   return path;
 }