[WebRTC] Add ScreenCapturerDifferWrapper to share Differ across ScreenCapturers

webrtc/modules/desktop_capture/differ_vector_sse2.h

Index: webrtc/modules/desktop_capture/differ_vector_sse2.h
diff --git a/webrtc/modules/desktop_capture/differ_vector_sse2.h b/webrtc/modules/desktop_capture/differ_vector_sse2.h
new file mode 100644
index 0000000000000000000000000000000000000000..353c6b9b00f11cb845b6de62f490159c2c4a62d4
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+++ b/webrtc/modules/desktop_capture/differ_vector_sse2.h
@@ -0,0 +1,31 @@
+/*
+ *  Copyright (c) 2016 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 vector difference.
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_VECTOR_SSE2_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_VECTOR_SSE2_H_
+
+#include <stdint.h>
+
+namespace webrtc {
+
+// Find vector difference of dimension 16.
+extern bool VectorDifference_SSE2_W16(const uint8_t* image1,
+                                      const uint8_t* image2);
+
+// Find vector difference of dimension 32.
+extern bool VectorDifference_SSE2_W32(const uint8_t* image1,
+                                      const uint8_t* image2);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_VECTOR_SSE2_H_