Add better bounds checks for getTime to fix perf debug assert below

src/utils/SkCurveMeasure.h

Index: src/utils/SkCurveMeasure.h
diff --git a/src/utils/SkCurveMeasure.h b/src/utils/SkCurveMeasure.h
index 2846103633145729861e63d7b282fcc5ee67defe..5807211236efbe96d146eff421f096e5697e7957 100644
--- a/src/utils/SkCurveMeasure.h
+++ b/src/utils/SkCurveMeasure.h
@@ -44,6 +44,15 @@ private:
 class SkCurveMeasure {
 public:
     SkCurveMeasure() {}
+
+    // Almost exactly the same as in SkPath::Iter:
+    // kLine_SegType  -> 2 points: start end
+    // kQuad_SegType  -> 3 points: start control end
+    // kCubic_SegType -> 4 points: start control1 control2 end
+    // kConic_SegType -> 4 points: start control end (w, w)
+    //
+    // i.e. the only difference is that the conic's last point is a point
+    // consisting of the w value twice
     SkCurveMeasure(const SkPoint* pts, SkSegType segType);
 
     SkScalar getTime(SkScalar targetLength);
@@ -51,13 +60,6 @@ public:
     SkScalar getLength();
 
 private:
-    SkPoint evaluateQuad(SkScalar t);
-    SkVector evaluateQuadDerivative(SkScalar t);
-    //SkPoint evaluate_cubic(SkScalar t);
-    //SkVector evaluate_cubic_derivative(SkScalar t);
-    //SkPoint evaluate_conic(SkScalar t);
-    //SkVector evaluate_conic_derivative(SkScalar t);
-
     const SkScalar kTolerance = 0.0001f;
     const int kNewtonIters = 5;
     const int kBisectIters = 5;