Move PiP when it occludes a keep clear area with naive algorithm.

This does not adjust the position of PiP after user manipulation,
i.e. PiP can occlude keep clear areas if user drags it on top of them.

Video of the behavior: http://recall/-/g8x7ZkgdfbqscttAA9wzl9/gDH7SgnC3nVLM0FBfWq8iU
Bug: 183746978
Test: manually on device, atest PipKeepClearAlgorithmTest
Change-Id: I3cbc46170df84954f40ff1484aa53ca374f9ce18