Use named guide to position popup image and text instead of manually

This CL uses a named guide to position the popup cell's leading image and
text instead of manually setting these constraints. This will help keep
those aligned and should make RTL support easier.

This also uses the flag value to choose which view controller to show.

Bug: 945323
Change-Id: I08b1160b0b2d1dd18b062ff6921915ca0b208d21
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1552865
Commit-Queue: Robbie Gibson <rkgibson@google.com>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#648621}
9 files changed