Add a new priority PRIORITY_DEVICE_PEAK_REFRESH_RATE, and a new config
setting config_defaultRefreshRate which maps to that priority. This
allows an OEM to easily specify a default frame rate different from the
peak frame rate.
Bug: 148978450
Bug: 154648391
Test: - Added new unit tests to verify DisplayModeDirector handles min,
peak, and default refresh rate settings correctly.
- Modified a sweet to set config_defaultRefreshRate to 60Hz, confirmed
we default to 60, but that an app calling setFrameRate(120) switches us
to 120.
- Confirmed that the "smooth display" and "force 120Hz" options on Razer
Phone work correctly.
- Confirmed Redfin works as it did before - still constrained to 60Hz.
Change-Id: Ibfc35abed2b67093b8114822d233bf1ca31eebb0