Fixes a crash on ChromeOS caused by a missing null check.

On ChromeOS, we don't provide a BadgeManagerDelegate so there was a
crash when attempting to notify the delegate that a badge change had
been ignored.

Bug: 984732
Change-Id: I74e8acb36d6246051e0de08c4550bde0888bac43
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1703488
Commit-Queue: Jay Harris <harrisjay@chromium.org>
Auto-Submit: Jay Harris <harrisjay@chromium.org>
Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#678166}
3 files changed