[GN] Prefer explicit pool to automatic link_pool for link targets.

In preparation of refactoring the concurrent_links code to use
explicit pools, prefer to use an explicit pool if defined over
the automatic link_pool for link targets.

BUG=612786

Review-Url: https://codereview.chromium.org/2182093002
Cr-Original-Commit-Position: refs/heads/master@{#408077}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 1c27131e1bf77b059ef4c4f444bdccecdddeb0f6
1 file changed
tree: faa635e96925ca51b2c10aa5414f161200710fb3
  1. tools/