Create BubbleControllerTest

- Introduce a resizability checker for easier testing
- Add a TestActivity to multivalent tests
- Add BubbleControllerTest (only testing one thing for now)

Bug: 216523800
Test: atest BubbleControllerTest
Flag: EXEMPT adding test
Change-Id: I62fdfeffaa454de589426b17e21a248a134a3c3e