scheduler: Move various files in renderer/ to main_thread/.

This patch moves source files that only serve the main thread scheduler
from renderer/ to main_thread/, which is the new home for those files
after the ongoing scheduler architecture refactoring.

All moved headers are only included from main_thread/, with the
exception of auto_advancing_virtual_time_domain.h which is used by a
test in common/, which should be OK.

Bug: 826203
Change-Id: I7ea7594cca5c2ebf66805db0dfacd0183cc7a6d4
Reviewed-on: https://chromium-review.googlesource.com/1038944
Commit-Queue: Yuta Kitamura <yutak@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556386}
40 files changed