fix bugs found by computing flat clips in 800K skps

src/pathops/SkDQuadLineIntersection.cpp

 /*
  * 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 "SkIntersections.h"
 #include "SkPathOpsLine.h"
 #include "SkPathOpsQuad.h"
 
@@ skipping 220 matching lines @@
             fIntersections->insert(quadT, lineT, fQuad[qIndex]);
         }
     }
 
     void addNearEndPoints() {
         for (int qIndex = 0; qIndex < 3; qIndex += 2) {
             double quadT = (double) (qIndex >> 1);
             if (fIntersections->hasT(quadT)) {
                 continue;
             }
-            double lineT = fLine.nearPoint(fQuad[qIndex]);
+            double lineT = fLine.nearPoint(fQuad[qIndex], NULL);
             if (lineT < 0) {
                 continue;
             }
             fIntersections->insert(quadT, lineT, fQuad[qIndex]);
         }
         // FIXME: see if line end is nearly on quad
     }
 
     void addExactHorizontalEndPoints(double left, double right, double y) {
         for (int qIndex = 0; qIndex < 3; qIndex += 2) {
@@ skipping 65 matching lines @@
             return false;
         }
         double qT = *quadT = SkPinT(*quadT);
         double lT = *lineT = SkPinT(*lineT);
         if (lT == 0 || lT == 1 || (ptSet == kPointUninitialized && qT != 0 && qT != 1)) {
             *pt = fLine.ptAtT(lT);
         } else if (ptSet == kPointUninitialized) {
             *pt = fQuad.ptAtT(qT);
         }
         SkPoint gridPt = pt->asSkPoint();
-        if (gridPt == fLine[0].asSkPoint()) {
+        if (SkDPoint::ApproximatelyEqual(gridPt, fLine[0].asSkPoint())) {
             *pt = fLine[0];
             *lineT = 0;
-        } else if (gridPt == fLine[1].asSkPoint()) {
+        } else if (SkDPoint::ApproximatelyEqual(gridPt, fLine[1].asSkPoint())) {
             *pt = fLine[1];
             *lineT = 1;
         }
         if (fIntersections->used() > 0 && approximately_equal((*fIntersections)[1][0], *lineT)) {
             return false;
         }
         if (gridPt == fQuad[0].asSkPoint()) {
             *pt = fQuad[0];
             *quadT = 0;
         } else if (gridPt == fQuad[2].asSkPoint()) {
@@ skipping 31 matching lines @@
 }
 
 int SkIntersections::intersectRay(const SkDQuad& quad, const SkDLine& line) {
     LineQuadraticIntersections q(quad, line, this);
     fUsed = q.intersectRay(fT[0]);
     for (int index = 0; index < fUsed; ++index) {
         fPt[index] = quad.ptAtT(fT[0][index]);
     }
     return fUsed;
 }