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- When the tab strip is closed, the newly activated tab should be
moved to the beginning of the list.
- When the tab strip is open, the newly activated tab should just
be scrolled to.
- Whenever the tab strip switches from visible to hidden, the active
tab should be moved to the beginning. The idea is what when a tab is
activated, the tab strip will close and the active tab will be then
be moved to avoid jumping while the tab strip is animating in and out.
- Regardless of whether or not the tab strip is visible, newly created
active tabs should be created at the beginning of the list to enforce
the MRU model.
- Disable drag and drop for unpinned tabs.

Bug: 1005554
Change-Id: I35f16ae111d949326533f45ce1d9494f578b774e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1829555
Commit-Queue: John Lee <johntlee@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702565}