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This is a heavy animation as it basically calls into UpdateResize which
resizes both windows (or one window and overview). Also, changes the
animation to use a runner which is synced with the compositor.

Test: none, will update tast-tests
Bug: 1047495
Change-Id: Ic29eb0dd831e7bbc5115268f8c09718b6fc82796
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2254820Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782707}