GitLab

Avoids need to take a lock in ::Trace by changing from an Oilpan-managed
|live_seekable_range_| to plain boolean/double members in MediaSource.

BUG=1162613,878133

Change-Id: Ic437b4b6f1143faad98750bd6c1d2a9791907ac4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2617351
Auto-Submit: Matthew Wolenetz <wolenetz@chromium.org>
Reviewed-by: Will Cassella <cassew@google.com>
Commit-Queue: Matthew Wolenetz <wolenetz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842175}