The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5c13715103310ff530824f2f5e3eda4e9f430240

commit 5c13715103310ff530824f2f5e3eda4e9f430240
Author: mrefaat <mrefaat@chromium.org>
Date: Wed Oct 24 20:49:19 2018

[IOSTabRefactoring] Remove urlDisplayString from tab

This is not used at all.

Bug:  898380 
Change-Id: I67a86391bb99204932f2bf3f7b680f0908d22801
Reviewed-on: https://chromium-review.googlesource.com/c/1298237
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Mohammad Refaat <mrefaat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602442}
[modify] https://crrev.com/5c13715103310ff530824f2f5e3eda4e9f430240/ios/chrome/browser/tabs/tab.h
[modify] https://crrev.com/5c13715103310ff530824f2f5e3eda4e9f430240/ios/chrome/browser/tabs/tab.mm