Make imagediff build on Win64

tools/imagediff/image_diff.cc

 // 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.
 
 // This file input format is based loosely on
 // Tools/DumpRenderTree/ImageDiff.m
 
 // The exact format of this tool's output to stdout is important, to match
 // what the run-webkit-tests script expects.
 
 #include <algorithm>
 #include <vector>
 #include <string>
 #include <iostream>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/process_util.h"
+#include "base/safe_numerics.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/size.h"
 
 #if defined(OS_WIN)
 #include "windows.h"
 #endif
 
 // Causes the app to remain open, waiting for pairs of filenames on stdin.
@@ skipping 281 matching lines @@
   bool same = CreateImageDiff(baseline_image, actual_image, &diff_image);
   if (same)
     return kStatusSame;
 
   std::vector<unsigned char> png_encoding;
   gfx::PNGCodec::Encode(diff_image.data(), gfx::PNGCodec::FORMAT_RGBA,
                         gfx::Size(diff_image.w(), diff_image.h()),
                         diff_image.w() * 4, false,
                         std::vector<gfx::PNGCodec::Comment>(), &png_encoding);
   if (file_util::WriteFile(out_file,
-      reinterpret_cast<char*>(&png_encoding.front()), png_encoding.size()) < 0)
+          reinterpret_cast<char*>(&png_encoding.front()),
+          base::checked_numeric_cast<int>(png_encoding.size())) < 0)
     return kStatusError;
 
   return kStatusDifferent;
 }
 
 // It isn't strictly correct to only support ASCII paths, but this
 // program reads paths on stdin and the program that spawns it outputs
 // paths as non-wide strings anyway.
 base::FilePath FilePathFromASCII(const std::string& str) {
 #if defined(OS_WIN)
@@ skipping 38 matching lines @@
                         base::FilePath(args[1]),
                         base::FilePath(args[2]));
     }
   } else if (args.size() == 2) {
     return CompareImages(base::FilePath(args[0]), base::FilePath(args[1]));
   }
 
   PrintHelp();
   return kStatusError;
 }