Current implementation builds targets consequently, i.e. one at a time. A more efficient option would be to pass all the targets to ninja at once, so that parallel linking can be done. However, there are following potential issues:

1) link pool limits may need to be adjusted: https://cs.chromium.org/chromium/src/build/toolchain/concurrent_links.gni?sq=package:chromium&dr=C&l=28

2) it's going to be harder for debugging with current implementation in bash scripts (https://chrome-internal.googlesource.com/chrome/tools/code-coverage/+/master/scripts/)

3) we'll eventually face this issue once we start building using Chrome Infra recipes, that's when we'll take a closer look