GitLab

Remove deprecated_default_sources_assignment_filter and replace
it with explicit is_win, is_mac, etc. sections.

Bug: 1018739
Change-Id: I37d6a625c366cbe94f16be2816fc51862efd90f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442541Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813157}