Avoid using WTF threading code in cc

cc/CCScopedThreadProxy.h

 // Copyright 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.
 
 #ifndef CCScopedThreadProxy_h
 #define CCScopedThreadProxy_h
 
 #include "CCThreadTask.h"
+#include "base/threading/platform_thread.h"
 #include <wtf/ThreadSafeRefCounted.h>
 
 namespace WebCore {
 
 // This class is a proxy used to post tasks to an target thread from any other thread. The proxy may be shut down at
 // any point from the target thread after which no more tasks posted to the proxy will run. In other words, all
 // tasks posted via a proxy are scoped to the lifecycle of the proxy. Use this when posting tasks to an object that
 // might die with tasks in flight.
 //
 // The proxy must be created and shut down from the target thread, tasks may be posted from any thread.
 //
 // Implementation note: Unlike ScopedRunnableMethodFactory in Chromium, pending tasks are not cancelled by actually
 // destroying the proxy. Instead each pending task holds a reference to the proxy to avoid maintaining an explicit
 // list of outstanding tasks.
 class CCScopedThreadProxy : public ThreadSafeRefCounted<CCScopedThreadProxy> {
 public:
     static PassRefPtr<CCScopedThreadProxy> create(CCThread* targetThread)
     {
-        ASSERT(currentThread() == targetThread->threadID());
+        ASSERT(base::PlatformThread::CurrentId() == targetThread->threadID());
         return adoptRef(new CCScopedThreadProxy(targetThread));
     }
 
     // Can be called from any thread. Posts a task to the target thread that runs unless
     // shutdown() is called before it runs.
     void postTask(PassOwnPtr<CCThread::Task> task)
     {
         ref();
         m_targetThread->postTask(createCCThreadTask(this, &CCScopedThreadProxy::runTaskIfNotShutdown, task));
     }
 
     void shutdown()
     {
-        ASSERT(currentThread() == m_targetThread->threadID());
+        ASSERT(base::PlatformThread::CurrentId() == m_targetThread->threadID());
         ASSERT(!m_shutdown);
         m_shutdown = true;
     }
 
 private:
     explicit CCScopedThreadProxy(CCThread* targetThread)
         : m_targetThread(targetThread)
         , m_shutdown(false) { }
 
     void runTaskIfNotShutdown(PassOwnPtr<CCThread::Task> popTask)
     {
         OwnPtr<CCThread::Task> task = popTask;
         // If our shutdown flag is set, it's possible that m_targetThread has already been destroyed so don't
         // touch it.
         if (m_shutdown) {
             deref();
             return;
         }
-        ASSERT(currentThread() == m_targetThread->threadID());
+        ASSERT(base::PlatformThread::CurrentId() == m_targetThread->threadID());
         task->performTask();
         deref();
     }
 
     CCThread* m_targetThread;
     bool m_shutdown; // Only accessed on the target thread
 };
 
 }
 
 #endif