Copy WindowState Bounds before modifying them

It is not safe to modify bounds returned by
getBounds, so it is important to copy them.

Change-Id: Ic19ed5e0326dc427fc6e38695fc5760980315599
Bug: 273045619
Test: build passes
Merged-In: I625afa17711fcd52bbb7fe9a9ba51500eb1bef5c