Make the fuchsia mojo/public repo the source of truth.

mojo/public/c/include/MGL/mgl_signal_sync_point.h

-// 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.
-
-// Note: This header should be compilable as C.
-
-#ifndef MOJO_PUBLIC_C_INCLUDE_MGL_MGL_SIGNAL_SYNC_POINT_H_
-#define MOJO_PUBLIC_C_INCLUDE_MGL_MGL_SIGNAL_SYNC_POINT_H_
-
-#include <MGL/mgl_types.h>
-#include <mojo/macros.h>
-#include <stdint.h>
-
-MOJO_BEGIN_EXTERN_C
-
-typedef void (*MGLSyncPointCallback)(void* closure);
-
-// MGLSignalSyncPoint signals the given sync point in the current context and
-// invokes |callback| when the service side acknowleges that the sync point has
-// been passed.
-void MGLSignalSyncPoint(uint32_t sync_point,
-                        MGLSignalSyncPointCallback callback,
-                        void* closure);
-
-MOJO_END_EXTERN_C
-
-#endif  // MOJO_PUBLIC_C_INCLUDE_MGL_MGL_SIGNAL_SYNC_POINT_H_