Enabling the canvas bit to turn the clip stack into a flat replace exposed around 100 failures when testing the 800K skp set generated from the top 1M web sites.

This fixes all but one of those failures.

Major changes include:
- Replace angle indices with angle pointers. This was motivated by the need to add angles later but not renumber existing angles.
- Aggressive segment chase. When the winding is known on a segment, more aggressively passing that winding to adjacent segments allows fragmented data sets to succeed.
- Line segments with ends nearly the same are treated as coincident first.
- Transfer partial coincidence by observing that if segment A is partially coincident to B and C then B and C may be partially coincident.

TBR=reed

Author: caryclark@google.com

Review URL: https://codereview.chromium.org/272153002
diff --git a/tests/PathOpsCubicIntersectionTest.cpp b/tests/PathOpsCubicIntersectionTest.cpp
index 17b3f07..b6a9e59 100644
--- a/tests/PathOpsCubicIntersectionTest.cpp
+++ b/tests/PathOpsCubicIntersectionTest.cpp
@@ -162,6 +162,9 @@
 const int testSetCount = (int) SK_ARRAY_COUNT(testSet);
 
 static const SkDCubic newTestSet[] = {
+{{{980.9000244140625, 1474.3280029296875}, {980.9000244140625, 1474.3280029296875}, {978.89300537109375, 1471.95703125}, {981.791015625, 1469.487060546875}}},
+{{{981.791015625, 1469.487060546875}, {981.791015625, 1469.4859619140625}, {983.3580322265625, 1472.72900390625}, {980.9000244140625, 1474.3280029296875}}},
+
 {{{275,532}, {277.209137,532}, {279,530.209106}, {279,528}}},
 {{{278,529}, {278,530.65686}, {276.65686,532}, {275,532}}},