GitLab

Convert IOSTranslateDriver to directly track registration with
the observed WebState instead of relying on the deprecated
code in WebStateObserver.

Bug: 775684
Change-Id: Iad1d53fcab9448e088a19cd75767235f9816a0b3
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Reviewed-on: https://chromium-review.googlesource.com/757105
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515956}