Remove NotificationImageReporter since it the backend support is not planned

R=nparker

Bug: 837707,836359,831563
Change-Id: Ice5c619948e47a3df6a257fc062ab9d38928bbab
Reviewed-on: https://chromium-review.googlesource.com/1139032
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Nathan Parker <nparker@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576175}
19 files changed