Merge r293182 - Add a helper function in TabObserver.java to handle WebContents Instant support disabled event.

Server side bug: b/17140979

BUG=411385
TEST=none
TBR=yfriedman@chromium.org

Review URL: https://codereview.chromium.org/532283003

Cr-Commit-Position: refs/heads/master@{#293182}
(cherry picked from commit ce3ea2a908ea4dab3565119ddc49eaa8380a8216)

Review URL: https://codereview.chromium.org/555493004
3 files changed