New path interpolation to paint vector drawables

Before this CL, PathMeasure_Delegate would use Path_Delegate.approximate
to get a path segment to draw. Path_Delegate.approximate uses a
flattening iterator to do the path approximation.
Unfortunately, because we do not control the stroke mode while painting,
in some cases the approximation would draw unwanted artifacts caused by
the rough approximation and the use of wrong miter values.
This CL does a much better calculation of the path and interpolates the
segments of the curves instead of replacing them with line segments.

This also fixes an issue with the calculation of empty paths.

Bug: http://b.android.com/187256

Change-Id: I450f7aa4c3d9efcbf902a40c3b4d6d388546893f