[WebRTC] Add ScreenCapturerDifferWrapper to share Differ across ScreenCapturers

webrtc/modules/desktop_capture/differ_block_sse2.h

-/*
- *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-// This header file is used only differ_block.h. It defines the SSE2 rountines
-// for finding block difference.
-
-#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_BLOCK_SSE2_H_
-#define WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_BLOCK_SSE2_H_
-
-#include <stdint.h>
-
-namespace webrtc {
-
-// Find block difference of dimension 16x16.
-extern bool BlockDifference_SSE2_W16(const uint8_t* image1,
-                                     const uint8_t* image2,
-                                     int stride);
-
-// Find block difference of dimension 32x32.
-extern bool BlockDifference_SSE2_W32(const uint8_t* image1,
-                                     const uint8_t* image2,
-                                     int stride);
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_BLOCK_SSE2_H_