Don't use exec_script() to get versionCode when build_with_chromium Trying to make "gn gen" faster. Bug: chromium:416002047 Change-Id: I11de9118b29b7ba9d139239730f2e3a23b1dad0d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6512333 Reviewed-by: Yuxin Hu <yuxinhu@google.com> Auto-Submit: Andrew Grieve <agrieve@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Yuly Novikov <ynovikov@chromium.org>