Fix get_syzygy_binaries.py on cygwin

get_syzygy_binaries.py errors out on cygwin, as it sends a temporary path in Cygwin form to gsutil, though gsutil is now run through depot_tools' python. This change makes the temporary path a Windows path so gsutil can read it.

Bug: 
Change-Id: I7bbabfb23b6925f0c8df5ba216506b7a6be0a021
Reviewed-on: https://chromium-review.googlesource.com/746202
Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: Chris Nardi <hichris123@gmail.com>
Cr-Original-Commit-Position: refs/heads/master@{#514007}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 5ed3d83dd03074884fc658a4b04b531ca05c619b

get_syzygy_binaries.py

@@ -281,8 +281,14 @@ def _Download(resource):
   """Downloads the given GS resource to a temporary file, returning its path."""
   tmp = tempfile.mkstemp(suffix='syzygy_archive')
   os.close(tmp[0])
+  tmp_file = tmp[1]
   url = 'gs://syzygy-archive' + resource
-  _GsUtil('cp', url, tmp[1])
+  if sys.platform == 'cygwin':
+    # Change temporary path to Windows path for gsutil
+    def winpath(path):
+      return subprocess.check_output(['cygpath', '-w', path]).strip()
+    tmp_file = winpath(tmp_file)
+  _GsUtil('cp', url, tmp_file)
   return tmp[1]