Add general-purpose vlogs for ax_image_annotator.

This is enough to quickly check how many images it's trying to label
and what successes we got back. To use, run Chrome with:

--enable-logging=stderr --vmodule="*ax_image_annotator*=1"

Bug: 905419
Change-Id: If3ceedbbb1a4d673f2045319836046690ccf7ed9
Reviewed-on: https://chromium-review.googlesource.com/c/1493198
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Katie Dektar <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636730}
2 files changed