GitLab

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

Bug: 1018739
Change-Id: I804134a7a0042fb2c1172e4d5163f760178a8ee8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442737Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813148}