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Removes the BVWrangler from the temporary interface, and instead sets
up a more permanent scheme:
1. SceneState exposes an interface provider
2. AppState allows access to SceneStates
3. MainController uses AppState's scenes to find an interface provider.

Note that a lot of code in MainController still assumes a single window
and this is not fixed in this CL.

Also breaks down application_delegate_internal target by splitting
out tab_opening. This allows to avoid a deps cycle.

Bug: 1045660
Change-Id: Iabd71bc18c901d6990dfdec77190605c4f51cb0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2120404Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753966}