TouchLatency: make updates time based and add fps to ball mode

Make ball updates time based instead of based on number of onDraw calls.
Also adding fps count to see how often frames are being updated, make
the color of the ball based on fps. This helps notice when there are
possible janks or change in refresh rate.

Test: gradlew build and run manual test of TouchLatency app
Change-Id: Ic2c2eb0fbd9fb31dddeee3228d6ab971a4f7f5e8