Make `python build/vs_toolchain.py update` mostly work on non-Windows.

1. GetFileList() returns a list of path\names on Windows but of path/names on
   non-Windows. To not perturb existing hashes, I guess the hashing code should do
   path.replace('/', '\\') before hashing.

2. GetFileList() returns a sorted list of filenames, and \ compares pretty
   different than / (the former is less than all numbers while the latter
   is greater, for example).  So replace / with \\ for sorting too.

With this change, OS X produces the same file hash as Windows.

The script still early-exits on non-Windows, so no visible change yet.

BUG=495204

Review URL: https://codereview.chromium.org/1287543005

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@296271 0039d316-1c4b-4281-b951-d872f2087c98

win_toolchain/get_toolchain_if_necessary.py

@@ -57,7 +57,7 @@ def GetFileList(root):
   for base, _, files in os.walk(root):
     paths = [os.path.join(base, f) for f in files]
     file_list.extend(x.lower() for x in paths)
-  return sorted(file_list)
+  return sorted(file_list, key=lambda s: s.replace('/', '\\'))
 
 
 def MakeTimestampsFileName(root):
@@ -93,7 +93,7 @@ def CalculateHash(root):
 
   digest = hashlib.sha1()
   for path in file_list:
-    digest.update(path)
+    digest.update(str(path).replace('/', '\\'))
     with open(path, 'rb') as f:
       digest.update(f.read())
   return digest.hexdigest()