Add quad to cubic bezier conversion utility to SkPath.

include/core/SkPath.h

 /*
  * 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.
  */
 
 #ifndef SkPath_DEFINED
 #define SkPath_DEFINED
 
@@ skipping 529 matching lines @@
     }
 
     /**
      *  Chop a conic into N quads, stored continguously in pts[], where
      *  N = 1 << pow2. The amount of storage needed is (1 + 2 * N)
      */
     static int ConvertConicToQuads(const SkPoint& p0, const SkPoint& p1, const SkPoint& p2,
                                    SkScalar w, SkPoint pts[], int pow2);
 
     /**
+     *  Given 3 points on a quadratic bezier, use degree elevation to
+     *  convert it into the cubic fitting the same curve. The new cubic
+     *  curve is returned in dst[0..3].
+     */
+    static void ConvertQuadToCubic(const SkPoint src[3], SkPoint dst[4]);
+
+    /**
      *  Returns true if the path specifies a rectangle.
      *
      *  If this returns false, then all output parameters are ignored, and left
      *  unchanged. If this returns true, then each of the output parameters
      *  are checked for NULL. If they are not, they return their value.
      *
      *  @param rect If not null, set to the bounds of the rectangle.
      *              Note : this bounds may be smaller than the path's bounds, since it is just
      *              the bounds of the "drawable" parts of the path. e.g. a trailing MoveTo would
      *              be ignored in this rect, but not by the path's bounds
@@ skipping 535 matching lines @@
 
     friend class SkAutoPathBoundsUpdate;
     friend class SkAutoDisableOvalCheck;
     friend class SkAutoDisableDirectionCheck;
     friend class SkBench_AddPathTest; // perf test reversePathTo
     friend class PathTest_Private; // unit test reversePathTo
     friend class ForceIsRRect_Private; // unit test isRRect
 };
 
 #endif