The approximation uses a similar error term as the fill scan converter to determine the number of quads to use.
This also updates SampleApp QuadStroker test with conics, ovals, and stroked text.
Review URL: https://codereview.chromium.org/932113002
Add RotateCircles3 back as better-named QuadStroker.
Switch pathfill test to call skia before draw instead of in
initializer to avoid triggering debugging breakpoints.
Review URL: https://codereview.chromium.org/912273003