GitLab

This CL also centralizes setting the activity's bounds and transform while in
split view to SplitViewController::UpdateLayout(). In particular, the bounds of
an activity are now correct even if it is opened while some other activity is
animating into split view

BUG=405964
TEST=WindowManagerTest.NewWindowBounds

Review URL: https://codereview.chromium.org/513313003

Cr-Commit-Position: refs/heads/master@{#293019}