Fix crash in computing main thread regions

Bug: 964293
Change-Id: I78171b3876a670c17c5b41112cdea943f109fa07
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1622908
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661932}
1 file changed