Move media library AutoTaskRunner to base and rename ScopedTaskRunner.

base/task.cc

Index: base/task.cc
diff --git a/base/task.cc b/base/task.cc
index d33f3e1a884fafa6013628150344b0c3d13ad394..dc58177d3aea38a4ac960d4523528ce9dd633478 100644
--- a/base/task.cc
+++ b/base/task.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -15,3 +15,23 @@ CancelableTask::CancelableTask() {
 
 CancelableTask::~CancelableTask() {
 }
+
+namespace base {
+
+ScopedTaskRunner::ScopedTaskRunner(Task* task) : task_(task) {
+}
+
+ScopedTaskRunner::~ScopedTaskRunner() {
+  if (task_) {
+    task_->Run();
+    delete task_;
+  }
+}
+
+Task* ScopedTaskRunner::Release() {
+  Task* tmp = task_;
+  task_ = NULL;
+  return tmp;
+}
+
+}