Track slow paths in DisplayItemList

cc/paint/paint_op_buffer_unittest.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/paint/paint_op_buffer.h"
 #include "cc/paint/display_item_list.h"
 #include "cc/test/skia_common.h"
 #include "cc/test/test_skcanvas.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/effects/SkDashPathEffect.h"
@@ skipping 475 matching lines @@
   buffer->push<ClipPathOp>(concave, SkClipOp::kIntersect, true);
   EXPECT_EQ(buffer->numSlowPaths(), 2);
   buffer->push<ClipPathOp>(concave, SkClipOp::kIntersect, false);
   EXPECT_EQ(buffer->numSlowPaths(), 2);
 
   // Drawing a record with slow paths into another adds the same
   // number of slow paths as the record.
   auto buffer2 = sk_make_sp<PaintOpBuffer>();
   EXPECT_EQ(buffer2->numSlowPaths(), 0);
   buffer2->push<DrawRecordOp>(buffer);
-  EXPECT_EQ(buffer->numSlowPaths(), buffer2->numSlowPaths());
+  EXPECT_EQ(buffer2->numSlowPaths(), 2);
+  buffer2->push<DrawRecordOp>(buffer);
+  EXPECT_EQ(buffer2->numSlowPaths(), 4);
+
+  // Drawing an empty display item list doesn't change anything.
+  auto empty_list = base::MakeRefCounted<DisplayItemList>();
+  buffer2->push<DrawDisplayItemListOp>(empty_list);
+  EXPECT_EQ(buffer2->numSlowPaths(), 4);
+
+  // Drawing a display item list adds the items from that list.
+  auto slow_path_list = base::MakeRefCounted<DisplayItemList>();
+  slow_path_list->CreateAndAppendDrawingItem<DrawingDisplayItem>(
+      gfx::Rect(1, 2, 3, 4), sk_make_sp<PaintOpBuffer>(),
+      SkRect::MakeXYWH(1, 2, 3, 4));
+  // Setting this properly is tested in PaintControllerTest.cpp.
+  slow_path_list->SetNumSlowPaths(50);
+  buffer2->push<DrawDisplayItemListOp>(slow_path_list);
+  EXPECT_EQ(buffer2->numSlowPaths(), 54);
 }
 
 }  // namespace cc