GitLab

Delete the signin::GetLandingURL() function.

This function isn't used anymore since crrev.com/c/1604274.

Bug: 470893
Test: existing unit tests
Change-Id: Ida6432f052d0b1980946366de567f4f5e56f00f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1606160
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660655}