binary_size: Remove legacy path, keep / as / for unittests on windows

tools/binary_size/explain_binary_size_delta.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Describe the size difference of two binaries.
 
 Generates a description of the size difference of two binaries based
 on the difference of the size of various symbols.
 
@@ skipping 48 matching lines @@
 
   cache1 = {}
   cache2 = {}
   # Make a map of (file, symbol_type) : (symbol_name, symbol_size)
   for cache, symbols in ((cache1, symbols1), (cache2, symbols2)):
     for symbol_name, symbol_type, symbol_size, file_path in symbols:
       if 'vtable for ' in symbol_name:
         symbol_type = '@' # hack to categorize these separately
       if file_path:
         file_path = os.path.normpath(file_path)
+        if sys.platform.startswith('win'):
+          file_path = file_path.replace('\\', '/')
       else:
         file_path = '(No Path)'
       key = (file_path, symbol_type)
       bucket = cache.setdefault(key, {})
       size_list = bucket.setdefault(symbol_name, [])
       size_list.append(symbol_size)
 
   # Now diff them. We iterate over the elements in cache1. For each symbol
   # that we find in cache2, we record whether it was deleted, changed, or
   # unchanged. We then remove it from cache2; all the symbols that remain
@@ skipping 272 matching lines @@
     with file(path, 'r') as nm_input:
       if opts.verbose:
         print 'parsing ' + path + '...'
       symbols.append(list(binary_size_utils.ParseNm(nm_input)))
   (added, removed, changed, unchanged) = Compare(symbols[0], symbols[1])
   CrunchStats(added, removed, changed, unchanged,
     opts.showsources | opts.showsymbols, opts.showsymbols)
 
 if __name__ == '__main__':
   sys.exit(main())