replace arcto quads with a conic

src/core/SkGeometry.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGeometry.h"
 #include "SkMatrix.h"
 #include "SkNx.h"
@@ skipping 933 matching lines @@
 bool SkChopMonoCubicAtY(SkPoint src[4], SkScalar y, SkPoint dst[7]) {
     return cubic_dchop_at_intercept(src, y, dst, &SkDCubic::horizontalIntersect);
 }
 
 bool SkChopMonoCubicAtX(SkPoint src[4], SkScalar x, SkPoint dst[7]) {
     return cubic_dchop_at_intercept(src, x, dst, &SkDCubic::verticalIntersect);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#ifdef SK_SUPPORT_LEGACY_ARCTO
 /*  Find t value for quadratic [a, b, c] = d.
     Return 0 if there is no solution within [0, 1)
 */
 static SkScalar quad_solve(SkScalar a, SkScalar b, SkScalar c, SkScalar d) {
     // At^2 + Bt + C = d
     SkScalar A = a - 2 * b + c;
     SkScalar B = 2 * (b - a);
     SkScalar C = a - d;
 
     SkScalar    roots[2];
@@ skipping 149 matching lines @@
     matrix.setSinCos(uStart.fY, uStart.fX);
     if (dir == kCCW_SkRotationDirection) {
         matrix.preScale(SK_Scalar1, -SK_Scalar1);
     }
     if (userMatrix) {
         matrix.postConcat(*userMatrix);
     }
     matrix.mapPoints(quadPoints, pointCount);
     return pointCount;
 }
-
+#endif
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 // NURB representation for conics.  Helpful explanations at:
 //
 // http://citeseerx.ist.psu.edu/viewdoc/
 //   download?doi=10.1.1.44.5740&rep=rep1&type=ps
 // and
 // http://www.cs.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/NURBS/RB-conics.html
 //
@@ skipping 457 matching lines @@
         matrix.preScale(SK_Scalar1, -SK_Scalar1);
     }
     if (userMatrix) {
         matrix.postConcat(*userMatrix);
     }
     for (int i = 0; i < conicCount; ++i) {
         matrix.mapPoints(dst[i].fPts, 3);
     }
     return conicCount;
 }