look for deleted pts when detecting line/curve coincident edges

tests/PathOpsBuilderTest.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 "PathOpsExtendedTest.h"
 #include "PathOpsTestCommon.h"
 #include "SkBitmap.h"
@@ skipping 60 matching lines @@
     Op(circle1, circle2, kUnion_SkPathOp, &opCompare);
     Op(opCompare, circle3, kDifference_SkPathOp, &opCompare);
     builder.add(circle1, kUnion_SkPathOp);
     builder.add(circle2, kUnion_SkPathOp);
     builder.add(circle3, kDifference_SkPathOp);
     REPORTER_ASSERT(reporter, builder.resolve(&result));
     SkBitmap bitmap;
     int pixelDiff = comparePaths(reporter, __FUNCTION__, opCompare, result, bitmap);
     REPORTER_ASSERT(reporter, pixelDiff == 0);
 }
+
+DEF_TEST(Issue3838, reporter) {
+    SkPath path;
+    path.moveTo(200, 170);
+    path.lineTo(220, 170);
+    path.lineTo(220, 230);
+    path.lineTo(240, 230);
+    path.lineTo(240, 210);
+    path.lineTo(180, 210);
+    path.lineTo(180, 190);
+    path.lineTo(260, 190);
+    path.lineTo(260, 250);
+    path.lineTo(200, 250);
+    path.lineTo(200, 170);
+    path.close();
+    testSimplify(reporter, path, __FUNCTION__);
+    SkPath path3;
+    Simplify(path, &path3);
+    SkPath path2;
+    SkOpBuilder builder;
+    builder.add(path, kUnion_SkPathOp);
+    builder.resolve(&path2);
+    SkBitmap bitmap;
+    int pixelDiff = comparePaths(reporter, __FUNCTION__, path, path2, bitmap);
+    REPORTER_ASSERT(reporter, pixelDiff == 0);
+}