Run Demuxer::GetMemoryUsage() on media thread
Split the memory usage reporting in WebMediaPlayerImpl into two steps so
that |demuxer_| can be accessed on the media thread only.
This change makes no practical difference for ChunkDemuxer ATM, which
uses locks extensively anyway. But it does make a difference for
FFmpegDemuxer (as evidenced by
https://codereview.chromium.org/1419753007 -- can be reverted now).
Also, other Chromium-based products are better off if Demuxer
implementations are not forced to worry about synchronization
themselves.
BUG=564034
TEST=Crash page from 447898 still doesn't crash
Review URL: https://codereview.chromium.org/1480213005
Cr-Commit-Position: refs/heads/master@{#362821}
2 files changed
