[SPv2] Decomposite otherwise-compositable animations that paint nothing.

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositorTest.cpp

 // Copyright 2016 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 "platform/graphics/compositing/PaintArtifactCompositor.h"
 
 #include <memory>
 
 #include "base/test/test_simple_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 103 matching lines @@
         ->property_trees()
         ->element_id_to_scroll_node_index[elementId];
   }
 
   const cc::TransformNode& transformNode(const cc::Layer* layer) {
     return *propertyTrees().transform_tree.Node(layer->transform_tree_index());
   }
 
   void update(const PaintArtifact& artifact) {
     std::unique_ptr<GeometryMapper> geometryMapper = GeometryMapper::create();
-    m_paintArtifactCompositor->update(artifact, nullptr, false,
-                                      *geometryMapper);
+    CompositorElementIdSet elementIds;
+    m_paintArtifactCompositor->update(artifact, nullptr, false, *geometryMapper,
+                                      elementIds);
     m_webLayerTreeView->layerTreeHost()->LayoutAndUpdateLayers();
   }
 
   cc::Layer* rootLayer() { return m_paintArtifactCompositor->rootLayer(); }
 
   size_t contentLayerCount() {
     return m_paintArtifactCompositor->getExtraDataForTesting()
         ->contentLayers.size();
   }
 
@@ skipping 1843 matching lines @@
   EXPECT_EQ(gfx::Size(50, 50), layer3->bounds());
   EXPECT_EQ(effectNode->id, layer3->effect_tree_index());
 
   const cc::Layer* layer4 = contentLayerAt(3);
   EXPECT_EQ(gfx::Vector2dF(100.f, 0.f), layer4->offset_to_transform_parent());
   EXPECT_EQ(gfx::Size(150, 150), layer4->bounds());
   EXPECT_EQ(1, layer4->effect_tree_index());
 }
 
 }  // namespace blink