Fix multi window thumbnail animation to the top of the screen.

mContainingFrame might be larger than mFrame in the free form stack. We
need to use the final frame to calculate where the animation goes. Also,
instead of detecting full screen and dialog windows, we can just check
if the window is free form to determine if we should use the multi
window animation.

Bug: 23554941
Change-Id: I71969aad5d39974b3da929aeed0b29ef9a71b516