fix path op conic bugs

tests/SubsetPath.h

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SubsetPath_DEFINED
+#define SubsetPath_DEFINED
+
+#include "SkPath.h"
+#include "SkTDArray.h"
+
+/* Given a path, generate a the desired minimal subset of the original.
+   
+   This does a binary divide-and-conquer on the path, first splitting by
+   contours, and then by verbs. The caller passes whether the previous subset
+   behaved the same as the original. If not, the subset() call restores the
+   prior state before returning a new subset.
+   
+   If a path fails a local test, this reduces the data to the
+   minimal set that fails using a pattern like:
+   
+   bool testFailed = true;
+   SkPath minimal;
+   SubsetContours subsetContours(testPath);
+   while (subsetContours.subset(testFailed, &minimal)) {
+       testFailed = myPathTest(minimal);
+   }
+   testFailed = true;
+   SubsetVerbs subsetVerbs(testPath);
+   while (subsetVerbs.subset(testFailed, &minimal)) {
+       testFailed = myPathTest(minimal);
+   }
+*/
+
+class SubsetPath {
+public:
+    SubsetPath(const SkPath& path);
+    virtual ~SubsetPath() {}
+    bool subset(bool testFailed, SkPath* sub);
+protected:
+    int range(int* end) const;
+    virtual SkPath getSubsetPath() const = 0;
+
+    const SkPath& fPath;
+    SkTDArray<bool> fSelected;
+    int fSubset;
+    int fTries;
+
+};
+
+class SubsetContours : public SubsetPath {
+public:
+    SubsetContours(const SkPath& path);
+protected:
+    SkPath getSubsetPath() const override;
+};
+
+class SubsetVerbs : public SubsetPath {
+public:
+    SubsetVerbs(const SkPath& path);
+protected:
+    SkPath getSubsetPath() const override;
+};
+
+#endif