Resubmit - Use SSE2 block differ for chromoting

remoting/host/differ.h

 // Copyright (c) 2010 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 REMOTING_HOST_DIFFER_H_
 #define REMOTING_HOST_DIFFER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 18 matching lines @@
 
   // Given the previous and current screen buffer, calculate the set of
   // rectangles that enclose all the changed pixels in the new screen.
   void CalcDirtyRects(const void* prev_buffer, const void* curr_buffer,
                       InvalidRects* rects);
 
   // Identify all of the blocks that contain changed pixels.
   void MarkDirtyBlocks(const void* prev_buffer, const void* curr_buffer);
 
   // Diff a small block of image and return non-zero if there is a diff.
-  // Currently, this just returns 0 or 1, but this may change in the future
-  // to return the number of pixels changed.
-  DiffInfo DiffBlock(const uint8* prev_buffer, const uint8* curr_buffer,
-                     int stride);
-
-  // Diff a small block of image and return non-zero if there is a diff.
   // This checks only the part of the block specified by the width and
   // height parameters.
   // This is much slower than DiffBlock() since it cannot assume that the
   // full block is being checked.
   // If we force the capturer to always return images whose width/height are
   // multiples of kBlockSize, then this will never be called.
   DiffInfo DiffPartialBlock(const uint8* prev_buffer, const uint8* curr_buffer,
                             int stride, int width, int height);
 
   // After the dirty blocks have been identified, this routine merges adjacent
@@ skipping 24 matching lines @@
   int diff_info_width_;
   int diff_info_height_;
   int diff_info_size_;
 
   DISALLOW_COPY_AND_ASSIGN(Differ);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_DIFFER_H_