GitLab

It's possible for BigBufferView::shared_memory_ to be null if memory
mapping fails. This change adds a check that the mapping is not null
before trying to write there.

Bug: 961256
Change-Id: I72772e07583ab62df5544d419604356071071e94
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1611311Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660010}