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* Move CenterWindow/CycleSnap to BaseState
* Updated CenterWindow to send event instead. This is
  is necessary in order for ClientControlledState to intercept
  bounds change request.
* Added animate parameter to SetBoundsEvent.

Animation on ARC++ windows are not implemented yet. It will
be handled in a separate CL.

BUG=b/30260227
TEST=covered by unittest

Change-Id: I7d3940f82f84331a717013005255e165818a7deb
Reviewed-on: https://chromium-review.googlesource.com/989837
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Qiang Xu <warx@google.com>
Cr-Commit-Position: refs/heads/master@{#547627}