Rewriting path writer

src/pathops/SkPathOpsTightBounds.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkOpEdgeBuilder.h"
 #include "SkPathOpsCommon.h"
 
 bool TightBounds(const SkPath& path, SkRect* result) {
     SkChunkAlloc allocator(4096);  // FIXME: constant-ize, tune
     SkOpContour contour;
     SkOpContourHead* contourList = static_cast<SkOpContourHead*>(&contour);
     SkOpGlobalState globalState(contourList, &allocator  SkDEBUGPARAMS(false)
             SkDEBUGPARAMS(nullptr));
     // turn path into list of segments
     SkScalar scaleFactor = ScaleFactor(path);
     SkPath scaledPath;
     const SkPath* workingPath;
     if (scaleFactor > SK_Scalar1) {
         ScalePath(path, 1.f / scaleFactor, &scaledPath);
         workingPath = &scaledPath;
     } else {
         workingPath = &path;
     }
-    SkOpEdgeBuilder builder(*workingPath, &contour, &globalState);
+    SkOpEdgeBuilder builder(*workingPath, contourList, &globalState);
     if (!builder.finish()) {
         return false;
     }
     if (!SortContourList(&contourList, false, false)) {
         result->setEmpty();
         return true;
     }
     SkOpContour* current = contourList;
     SkPathOpsBounds bounds = current->bounds();
     while ((current = current->next())) {
         bounds.add(current->bounds());
     }
     *result = bounds;
     return true;
 }