GN: Use all targets to determine whether a file is generated (for `check`).

BUG=562675

Review URL: https://codereview.chromium.org/1479313002

Cr-Original-Commit-Position: refs/heads/master@{#362135}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: b634f17a82d488df8851049c6ec2ad160b3547d3
1 file changed
tree: 10df47803e499a4d127b41e15bf27192b77b20df
  1. tools/