pip2: Always elide the URL in the titlebar

This CL ensures that the URL in a document picture-in-picture window is
always elided, even when the user has selected "Always Show Full URLs"
in the omnibox.

Bug: 1450376
Change-Id: I6275e0ff9d3a9a860e5e4086732d717c47bdc3fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4581312


Commit-Queue: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1152637}