Detect empty (r)rects in GrShape.

tests/GrShapeTest.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <initializer_list>
 #include <functional>
 #include "Test.h"
@@ skipping 532 matching lines @@
     stroke.setStyle(SkPaint::kStroke_Style);
     TestCase strokeEmptyCase(emptyPath2, stroke);
     strokeEmptyCase.compare(reporter, fillEmptyCase, TestCase::kAllSame_ComparisonExpecation);
 
     // Dashing and stroking an empty path should have no effect
     SkPath emptyPath3;
     SkPaint dashAndStroke;
     dashAndStroke.setPathEffect(make_dash());
     dashAndStroke.setStrokeWidth(2.f);
     dashAndStroke.setStyle(SkPaint::kStroke_Style);
-    TestCase dashAndStrokeEmptyCase(emptyPath3, stroke);
+    TestCase dashAndStrokeEmptyCase(emptyPath3, dashAndStroke);
     dashAndStrokeEmptyCase.compare(reporter, fillEmptyCase,
                                    TestCase::kAllSame_ComparisonExpecation);
+
+    // A shape made from an empty rrect should behave the same as an empty path.
+    SkRRect emptyRRect = SkRRect::MakeRect(SkRect::MakeEmpty());
+    REPORTER_ASSERT(reporter, emptyRRect.getType() == SkRRect::kEmpty_Type);
+    TestCase dashAndStrokeEmptyRRectCase(emptyRRect, dashAndStroke);
+    dashAndStrokeEmptyRRectCase.compare(reporter, fillEmptyCase,
+                                        TestCase::kAllSame_ComparisonExpecation);
+
+    // Same for a rect.
+    SkRect emptyRect = SkRect::MakeEmpty();
+    TestCase dashAndStrokeEmptyRectCase(emptyRect, dashAndStroke);
+    dashAndStrokeEmptyRectCase.compare(reporter, fillEmptyCase,
+                                       TestCase::kAllSame_ComparisonExpecation);
 }
 
 DEF_TEST(GrShape, reporter) {
     sk_sp<SkPathEffect> dashPE = make_dash();
 
     for (auto rr : { SkRRect::MakeRect(SkRect::MakeWH(10, 10)),
                      SkRRect::MakeRectXY(SkRect::MakeWH(10, 10), 3, 4)}) {
         test_basic(reporter, rr);
         test_dash_fill(reporter, rr);
         test_null_dash(reporter, rr);
@@ skipping 103 matching lines @@
         }
     }
 
     // Test a volatile empty path.
     test_volatile_path(reporter, SkPath(), true);
 
     test_empty_shape(reporter);
 }
 
 #endif