Do not include the leading point for cubic polylines (#29)

This avoids having duplicated points present in the polyline.

Author: dnfield

impeller/geometry/geometry_unittests.cc

@@ -6,6 +6,7 @@
 #include "flutter/testing/testing.h"
 #include "impeller/geometry/path.h"
 #include "impeller/geometry/path_builder.h"
+#include "impeller/geometry/path_component.h"
 #include "impeller/geometry/point.h"
 #include "impeller/geometry/rect.h"
 #include "impeller/geometry/size.h"
@@ -524,5 +525,15 @@ TEST(GeometryTest, RectContainsRect) {
   }
 }
 
+TEST(GeometryTest, CubicPathComponentPolylineDoesNotIncludePointOne) {
+  CubicPathComponent component({10, 10}, {20,35}, {35, 20}, {40, 40});
+  SmoothingApproximation approximation;
+  auto polyline = component.CreatePolyline(approximation);
+  ASSERT_NE(polyline.front().x, 10);
+  ASSERT_NE(polyline.front().y, 10);
+  ASSERT_EQ(polyline.back().x, 40);
+  ASSERT_EQ(polyline.back().y, 40);
+}
+
 }  // namespace testing
 }  // namespace impeller

impeller/geometry/path_component.cc

@@ -339,7 +339,6 @@ static void CubicPathSmoothenRecursive(const SmoothingApproximation& approx,
 std::vector<Point> CubicPathComponent::CreatePolyline(
     const SmoothingApproximation& approximation) const {
   std::vector<Point> points;
-  points.emplace_back(p1);
   CubicPathSmoothenRecursive(approximation, points, p1, cp1, cp2, p2, 0);
   points.emplace_back(p2);
   return points;