Fix BadgeServiceImpl::IsInApp

FindBrowserWithWebContents() may return null in some cases.
This cl check the return value first to avoid potential crahsed.

Bug: 962412
Change-Id: I4289155d2c95f4cf80d667b24b17fb94a9e4569c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1612578
Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Commit-Queue: Yining Wang <yiningwang@google.com>
Cr-Commit-Position: refs/heads/master@{#660032}
1 file changed