GitLab

This CL removes CRWWebController.referrerFromNavigationAction which is
not a very helpful method. The HTTP header constant "Referer" is moved
into wk_navigation_util.h/mm for possible reuse.

Bug: 956511
Change-Id: I8036c773c2dabde04282e93b34d97e89940ca191
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1599588
Commit-Queue: Yi Su <mrsuyi@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658991}