Convert to new enter method

ppapi/thunk/common.h

-// 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.
-
-#ifndef PPAPI_THUNK_COMMON_H_
-#define PPAPI_THUNK_COMMON_H_
-
-#include "ppapi/c/pp_completion_callback.h"
-
-namespace ppapi {
-namespace thunk {
-
-// Skips callback invocation and returns |result| if callback function is NULL
-// or PP_COMPLETIONCALLBACK_FLAG_OPTIONAL is set. Otherwise, schedules the
-// callback with |result| as an argument and returns PP_OK_COMPLETIONPENDING.
-int32_t MayForceCallback(PP_CompletionCallback callback, int32_t result);
-
-}  // namespace thunk
-}  // namespace ppapi
-
-#endif  // PPAPI_THUNK_COMMON_H_