gn: Don't do an out-of-bound access if a file ends after 'else'

BUG=640857

Review-Url: https://codereview.chromium.org/2282493002
Cr-Original-Commit-Position: refs/heads/master@{#414461}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 5aba5ce9d5f3184b1e659c319e962c57274cbe03
2 files changed
tree: a9595c3844988ab64807d263fec6d78f34c0790c
  1. tools/