Rewrite references to "wtf/" to "platform/wtf/" in the rest of platform/.

third_party/WebKit/Source/platform/threading/BackgroundTaskRunnerTest.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 <memory>
 #include "base/test/scoped_async_task_scheduler.h"
 #include "platform/CrossThreadFunctional.h"
 #include "platform/WaitableEvent.h"
+#include "platform/wtf/PtrUtil.h"
 #include "public/platform/WebTraceLocation.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "wtf/PtrUtil.h"
 
 namespace blink {
 
 namespace {
 
 void PingPongTask(WaitableEvent* done_event) {
   done_event->Signal();
 }
 
 }  // namespace
 
 TEST(BackgroundTaskRunnerTest, RunOnBackgroundThread) {
   base::test::ScopedAsyncTaskScheduler scoped_async_task_scheduler;
   std::unique_ptr<WaitableEvent> done_event = WTF::MakeUnique<WaitableEvent>();
   BackgroundTaskRunner::PostOnBackgroundThread(
       BLINK_FROM_HERE,
       CrossThreadBind(&PingPongTask, CrossThreadUnretained(done_event.get())));
   // Test passes by not hanging on the following wait().
   done_event->Wait();
 }
 
 }  // namespace blink