Observe the current configuration from DataReductionProxyURLLoaderThrottle.

Bug: 721403

Change-Id: I6f23e6ba1099666be58014efa840829a072b097c
Reviewed-on: https://chromium-review.googlesource.com/c/1347432
Reviewed-by: rajendrant <rajendrant@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611968}
16 files changed