Use SkJpegEncoder in WebKit platform

third_party/WebKit/Source/platform/image-encoders/RGBAtoRGB.h

-// Copyright 2016 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 RGBAtoRGB_h
-#define RGBAtoRGB_h
-
-// TODO(cavalcantii): use regular macro, see https://crbug.com/673067.
-#ifdef __ARM_NEON__
-#include <arm_neon.h>
-#define RGBAtoRGB RGBAtoRGBNeon
-#else
-#define RGBAtoRGB RGBAtoRGBScalar
-#endif
-
-#include "platform/PlatformExport.h"
-
-namespace blink {
-PLATFORM_EXPORT void RGBAtoRGBScalar(const unsigned char* pixels,
-                                     unsigned pixel_count,
-                                     unsigned char* output);
-#ifdef __ARM_NEON__
-PLATFORM_EXPORT void RGBAtoRGBNeon(const unsigned char* input,
-                                   const unsigned pixel_count,
-                                   unsigned char* output);
-#endif
-
-}  // namespace blink
-
-#endif