Settings: Focus on last selected item in All Sites.

After adding list repopulation whenever the All Sites page is loaded
(r1428622), the feature that focus on last selected item stopped working.
This CL fixes this issue. This CL also changes the Site Entry usage info
fetching code slightly. This is because the change of the focus changes the
items in the list that is rendered in the DOM. If the later focused item have
0 data, it will generate the string without sending request to C++ code, and
the feedback from C++ code from the original request will overwrite the 0B
string because it takes longer.

BUG=835712

Change-Id: I0af72a67cd621b7e94941aac4e687103191fcc39
Reviewed-on: https://chromium-review.googlesource.com/c/1451485
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Patti <patricialor@chromium.org>
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629418}
3 files changed