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The new  behaviors are:
1. When going to ambient mode page, keep user previous selection or
auto-select Art if no album or selected album is deleted.
2. Click Art row will always select Art row.
3. Click any place of `Google Photos' (GP) row, will not change the
selection status yet, but goes to the GP album-selection page. When user
makes any change on GP album-selection page, we will either select GP
row, or fall back to select Art row based on if any albums is available
or un/selected.
4. Any actives on the album-selection page without first going to the
ambient mode page, will trigger same behaviors as 2 & 3.
5. Click the topic source row and right arrow in that row will behave
the same.

Bug: b/161928422
Test: modified handler and js tests
Change-Id: Id5b33ca9a7cd712c899091796cbab461e9970141
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364167
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Jimmy Gong <jimmyxgong@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803781}