[IncognitoAware] Delay setting content view until showPopupWindow

The content view is not needed before the PopupWindow shows on the
screen. This change makes the AnchoredPopupWindow takes a view supplier,
and read the supplier when the content view is needed.

This change forward the existing caller to just create a new supplier
with the view that's readily inflated during popup window's creation. No
user visible impact is expected from this change. Lifecycle management
of the class will be done in the follow up work.

Bug: 439677294
Change-Id: I036add4ca3202a24602885dc80cccd84500583f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6862300
Reviewed-by: Sinan Sahin <sinansahin@google.com>
Reviewed-by: Mark Schillaci <mschillaci@google.com>
Commit-Queue: Wenyu Fu <wenyufu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1505140}