keep only one typedef for the native drawing context

skia/ext/platform_surface.h

-// Copyright (c) 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.
-
-#ifndef SKIA_EXT_PLATFORM_SURFACE_H_
-#define SKIA_EXT_PLATFORM_SURFACE_H_
-
-#include "build/build_config.h"
-
-#include "third_party/skia/include/core/SkTypes.h"
-#include "third_party/skia/include/core/SkRect.h"
-
-#if defined(OS_WIN)
-#include <windows.h>
-#elif defined(USE_CAIRO)
-typedef struct _cairo cairo_t;
-typedef struct _cairo_rectangle cairo_rectangle_t;
-#elif defined(OS_MACOSX)
-typedef struct CGContext* CGContextRef;
-typedef struct CGRect CGRect;
-#endif
-
-namespace skia {
-
-#if defined(OS_WIN)
-typedef HDC PlatformSurface;
-typedef RECT PlatformRect;
-#elif defined(USE_CAIRO)
-typedef cairo_t* PlatformSurface;
-typedef cairo_rectangle_t PlatformRect;
-#elif defined(OS_MACOSX)
-typedef CGContextRef PlatformSurface;
-typedef CGRect PlatformRect;
-#else
-typedef void* PlatformSurface;
-typedef SkIRect* PlatformRect;
-#endif
-
-}  // namespace skia
-
-#endif  // SKIA_EXT_PLATFORM_SURFACE_H_