Convert to new enter method

ppapi/thunk/common.cc

-// 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.
-
-#include "ppapi/thunk/common.h"
-
-#include "base/bind.h"
-#include "base/message_loop.h"
-#include "ppapi/c/pp_errors.h"
-
-namespace ppapi {
-namespace thunk {
-
-int32_t MayForceCallback(PP_CompletionCallback callback, int32_t result) {
-  if (result == PP_OK_COMPLETIONPENDING)
-    return result;
-
-  if (callback.func == NULL ||
-      (callback.flags & PP_COMPLETIONCALLBACK_FLAG_OPTIONAL) != 0)
-    return result;
-
-  // TODO(polina): make this work off the main thread as well
-  // (At this point this should not be an issue because PPAPI is only supported
-  // on the main thread).
-  MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
-      callback.func, callback.user_data, result));
-  return PP_OK_COMPLETIONPENDING;
-}
-
-}  // namespace thunk
-}  // namespace ppapi