Add thread affinity and ASSERT() for same-thread restriction to WTF::Function

third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp

 // Copyright 2015 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 "platform/threading/BackgroundTaskRunner.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/threading/worker_pool.h"
 #include "public/platform/WebTraceLocation.h"
 
 namespace blink {
 
-static void RunBackgroundTask(PassOwnPtr<Closure> closure)
+static void RunBackgroundTask(PassOwnPtr<CrossThreadClosure> closure)
 {
     (*closure)();
 }
 
-void BackgroundTaskRunner::postOnBackgroundThread(const WebTraceLocation& location, PassOwnPtr<Closure> closure, TaskSize taskSize)
+void BackgroundTaskRunner::postOnBackgroundThread(const WebTraceLocation& location, PassOwnPtr<CrossThreadClosure> closure, TaskSize taskSize)
 {
     tracked_objects::Location baseLocation(location.functionName(), location.fileName(), 0, nullptr);
     base::WorkerPool::PostTask(baseLocation, base::Bind(&RunBackgroundTask, closure), taskSize == TaskSizeLongRunningTask);
 }
 
 } // namespace blink