Define Chromoting's differ block size in one (and only one) place.

remoting/host/differ.h

 // Copyright (c) 2011 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"
 #include "base/memory/scoped_ptr.h"
 #include "remoting/base/types.h"
 #include "ui/gfx/rect.h"
 
 namespace remoting {
 
 typedef uint8 DiffInfo;
 
-// Size (in pixels) of each square block used for diffing.
-// This must be a multiple of sizeof(uint64).
-static const int kBlockSize = 32;
-
 class Differ {
  public:
   // Create a differ that operates on bitmaps with the specified width, height
   // and bytes_per_pixel.
   Differ(int width, int height, int bytes_per_pixel, int stride);
   ~Differ();
 
   int width() { return width_; }
   int height() { return height_; }
   int bytes_per_pixel() { return bytes_per_pixel_; }
@@ skipping 43 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_