Add ability to change PiP menu icon locations on the fly.

This CL does:
- Add a PipMenuIconsAlgorithm, allowing calculation on the fly for
correct locations of individual icons
- Make it so that when PIP changes its bounds, it updates the location
of the action items accordingly (if needed)

Bug: 160825579
Test: enter PIP, icons are still where they are
Change-Id: I8618f7c5c36c8e09613c126c1ebb20b60e95de58