path ops -- rewrite angle sort

src/pathops/SkPathOpsPoint.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkPathOpsPoint_DEFINED
 #define SkPathOpsPoint_DEFINED
 
 #include "SkPathOpsTypes.h"
@@ skipping 99 matching lines @@
                 && approximately_equal(fY * inv, a.fY * inv);
     }
 
     bool approximatelyEqual(const SkPoint& a) const {
         double denom = SkTMax(fabs(fX), SkTMax(fabs(fY),
                 SkScalarToDouble(SkTMax(fabsf(a.fX), fabsf(a.fY)))));
         if (denom == 0) {
             return true;
         }
         double inv = 1 / denom;
-        return approximately_equal(fX * inv, a.fX * inv)
-                && approximately_equal(fY * inv, a.fY * inv);
+        return approximately_equal_double(fX * inv, a.fX * inv)
+                && approximately_equal_double(fY * inv, a.fY * inv);
     }
 
     bool approximatelyEqualHalf(const SkDPoint& a) const {
         double denom = SkTMax(fabs(fX), SkTMax(fabs(fY),
                 SkTMax(fabs(a.fX), fabs(a.fY))));
         if (denom == 0) {
             return true;
         }
         double inv = 1 / denom;
         return approximately_equal_half(fX * inv, a.fX * inv)
@@ skipping 12 matching lines @@
     double distance(const SkDPoint& a) const {
         SkDVector temp = *this - a;
         return temp.length();
     }
 
     double distanceSquared(const SkDPoint& a) const {
         SkDVector temp = *this - a;
         return temp.lengthSquared();
     }
 
+    static SkDPoint Mid(const SkDPoint& a, const SkDPoint& b) {
+        SkDPoint result;
+        result.fX = (a.fX + b.fX) / 2;
+        result.fY = (a.fY + b.fY) / 2;
+        return result;
+    }
+
     double moreRoughlyEqual(const SkDPoint& a) const {
         return more_roughly_equal(a.fY, fY) && more_roughly_equal(a.fX, fX);
     }
 
     double roughlyEqual(const SkDPoint& a) const {
         return roughly_equal(a.fY, fY) && roughly_equal(a.fX, fX);
     }
 };
 
 #endif