Reland "Implement proposed bookmark UI"

This is a reland of commit bb3d7acf140d4f74da66faa9a90a0f6612935430 It
updates the old unit tests so that they can fit into the latest bookmark
UI design on tablets.

Original change's description:
> Implement proposed bookmark UI
>
> This change improves the user experience by keeping the page title and
> bookmarks list visible when the search field is focused with a physical
> keyboard which aligns the LFF bookmark manager with the convenience of
> desktop. See demo: http://shortn/_dKyLdqJkpG
>
> Bug: 421032963
> TEST: Added testSearchBarAutoFocus for the bookmark pane javatest
> Change-Id: I89884767937ca4ef627ded4b83c198e34ddf8e3c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6830828
> Commit-Queue: ben chin <lungc@chromium.org>
> Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
> Reviewed-by: Brandon Wylie <wylieb@google.com>
> Cr-Commit-Position: refs/heads/main@{#1501795}

Bug: 421032963
Change-Id: I62f72d80b38a53ae21b07b95ff40a42414a52014
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6866732
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: ben chin <lungc@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1506861}