GitLab

Clean up deprecated sources assignment filter in //content/test

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

Bug: 1018739
Change-Id: Ic7306c6f227ce0193402fe919a7a7a281fe9f927
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2446049
Commit-Queue: Scott Violet <sky@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814458}