Make "vs_toolchain.py update" work on case-sensitive file systems

Filenames must have their case preserved so the files can be opened,
but they need to be lowercased when hashed and sorted, to match the
expected hash.

In other words, this patch moves the lower-casing from GetFileList
(except to sort the list) to where filenames are fed into the hash.

BUG=495204

Review-Url: https://codereview.chromium.org/2039563002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300696 0039d316-1c4b-4281-b951-d872f2087c98

win_toolchain/get_toolchain_if_necessary.py

@@ -76,16 +76,20 @@ def GetFileList(root):
   # they crash. Also ignores the content of the win_sdk/debuggers/x(86|64)/sym/
   # directories as this is just the temporarily location that Windbg might use
   # to store the symbol files.
+  #
+  # Note: These files are only created on a Windows host, so the
+  # ignored_directories list isn't relevant on non-Windows hosts.
+
   ignored_directories = ['wer\\reportqueue',
                          'win_sdk\\debuggers\\x86\\sym\\',
                          'win_sdk\\debuggers\\x64\\sym\\']
   for base, _, files in os.walk(root):
-    paths = [os.path.join(base, f).lower() for f in files]
+    paths = [os.path.join(base, f) for f in files]
     for p in paths:
-      if any(ignored_dir in p for ignored_dir in ignored_directories):
+      if any(ignored_dir in p.lower() for ignored_dir in ignored_directories):
         continue
       file_list.append(p)
-  return sorted(file_list, key=lambda s: s.replace('/', '\\'))
+  return sorted(file_list, key=lambda s: s.replace('/', '\\').lower())
 
 
 def MakeTimestampsFileName(root, sha1):
@@ -158,7 +162,7 @@ def CalculateHash(root, expected_hash):
     if expected_hash:
       path_without_hash = path_without_hash.replace(
           os.path.join(root, expected_hash).replace('/', '\\'), root)
-    digest.update(path_without_hash)
+    digest.update(path_without_hash.lower())
     with open(path, 'rb') as f:
       digest.update(f.read())
   return digest.hexdigest()