win toolchain downloader: Don't omit hidden or system files.

Hashes for both the 2013 and 2015 toolchain don't change for me locally with
this change, looks like there are no hidden or system files in the toolchain.
(I tried with the "you are a googler" flow.)

No intended behavior change.

BUG=495204

Review URL: https://codereview.chromium.org/1200113004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295804 0039d316-1c4b-4281-b951-d872f2087c98

win_toolchain/get_toolchain_if_necessary.py

@@ -48,22 +48,6 @@ except ImportError:
   # on bare VM that doesn't have a full depot_tools.
   pass
 
-if sys.platform != 'cygwin':
-  import ctypes.wintypes
-  GetFileAttributes = ctypes.windll.kernel32.GetFileAttributesW
-  GetFileAttributes.argtypes = (ctypes.wintypes.LPWSTR,)
-  GetFileAttributes.restype = ctypes.wintypes.DWORD
-  FILE_ATTRIBUTE_HIDDEN = 0x2
-  FILE_ATTRIBUTE_SYSTEM = 0x4
-
-
-def IsHidden(file_path):
-  """Returns whether the given |file_path| has the 'system' or 'hidden'
-  attribute set."""
-  p = GetFileAttributes(file_path)
-  assert p != 0xffffffff
-  return bool(p & (FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM))
-
 
 def GetFileList(root):
   """Gets a normalized list of files under |root|."""
@@ -72,7 +56,7 @@ def GetFileList(root):
   file_list = []
   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 if not IsHidden(x))
+    file_list.extend(x.lower() for x in paths)
   return sorted(file_list)