Add shell=True for gn-format.py on Windows

Broken if gn.exe isn't in path (which it isn't if you're using the
depot_tools wrapper goop.)

Review URL: https://codereview.chromium.org/1892213002

Cr-Original-Commit-Position: refs/heads/master@{#387689}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 3a93fa5a544dc594288a725b34e6ecda8c718802
1 file changed
tree: 4fde294f036a35a4f36a154a201d1812a4b5ec63
  1. tools/