Add base types for path ops

src/pathops/SkPathOpsTriangle.cpp

Index: src/pathops/SkPathOpsTriangle.cpp
===================================================================
--- src/pathops/SkPathOpsTriangle.cpp	(revision 0)
+++ src/pathops/SkPathOpsTriangle.cpp	(revision 0)
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPathOpsTriangle.h"
+
+// http://www.blackpawn.com/texts/pointinpoly/default.html
+bool SkDTriangle::contains(const SkDPoint& pt) const {
+// Compute vectors
+    SkDVector v0 = fPts[2] - fPts[0];
+    SkDVector v1 = fPts[1] - fPts[0];
+    SkDVector v2 = pt - fPts[0];
+
+// Compute dot products
+    double dot00 = v0.dot(v0);
+    double dot01 = v0.dot(v1);
+    double dot02 = v0.dot(v2);
+    double dot11 = v1.dot(v1);
+    double dot12 = v1.dot(v2);
+
+// Compute barycentric coordinates
+    double invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
+    double u = (dot11 * dot02 - dot01 * dot12) * invDenom;
+    double v = (dot00 * dot12 - dot01 * dot02) * invDenom;
+
+// Check if point is in triangle
+    return (u >= 0) && (v >= 0) && (u + v < 1);
+}