Add intersections for path ops

src/pathops/SkDQuadImplicit.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 SkDQuadImplicit_DEFINED
+#define SkDQuadImplicit_DEFINED
+
+#include "SkPathOpsQuad.h"
+
+class SkDQuadImplicit {
+public:
+    explicit SkDQuadImplicit(const SkDQuad& q);
+
+    bool match(const SkDQuadImplicit& two) const;
+    static bool Match(const SkDQuad& quad1, const SkDQuad& quad2);
+
+    double x2() const { return fP[kXx_Coeff]; }
+    double xy() const { return fP[kXy_Coeff]; }
+    double y2() const { return fP[kYy_Coeff]; }
+    double x() const { return fP[kX_Coeff]; }
+    double y() const { return fP[kY_Coeff]; }
+    double c() const { return fP[kC_Coeff]; }
+
+private:
+    enum Coeffs {
+        kXx_Coeff,
+        kXy_Coeff,
+        kYy_Coeff,
+        kX_Coeff,
+        kY_Coeff,
+        kC_Coeff,
+    };
+
+    double fP[kC_Coeff + 1];
+};
+
+#endif