Move mojo/public/c/gpu/* to mojo/public/c/include.

mojo/public/c/gpu/MGL/mgl_onscreen.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_GPU_MGL_MGL_ONSCREEN_H_
-#define MOJO_PUBLIC_C_GPU_MGL_MGL_ONSCREEN_H_
-
-#include <stdint.h>
-
-#include "mojo/public/c/gpu/MGL/mgl_types.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// Resizes the default framebuffer for the currently bound onscreen MGLContext.
-void MGLResizeSurface(uint32_t width, uint32_t height);
-
-// Presents the default framebuffer for the currently bound onscreen MGLContext
-// to the windowing system or display.
-void MGLSwapBuffers(void);
-
-#ifdef __cplusplus
-}  // extern "C"
-#endif
-
-#endif  // MOJO_PUBLIC_C_GPU_MGL_MGL_ONSCREEN_H_