Reduce absolute paths in generated ninja files

After this change, the number of steps required for rebuilding all
after snapshot and "gn gen" is reduced to 711 (Linux Release build).

BUG=723856

Review-Url: https://codereview.chromium.org/2905523002
Cr-Original-Commit-Position: refs/heads/master@{#475458}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 5e1f7259d0638f865ed7f5a6c1ecabf5b9968e2c
1 file changed
tree: 8dd7ced1225bc2f405b99ab2858eb61bf80ba081
  1. OWNERS
  2. generate_library_loader.gni
  3. generate_library_loader.py