A stroked conic computes the outset quad's control point by
computing the intersection of the quad's endpoints. If the
the denominator used to compute the scale factor for the
control point is small, check to see if the numerator is also
small so that the division stays bounded.
Also clean up error returns and internal function calls to
simplify the code.
Additionally, remove comic max curvature (unimplemented) and call
extrema functions instead to handle cases where the conic is degenerate
or is a line.
R=reed@google.com, fmalita@chromium.org
BUG=skia:3843
Review URL: https://codereview.chromium.org/1144883003
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
