Switch to null root property tree nodes [spv2]

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

Index: third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp b/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp
index 79321fb3ed5ece415829117039910ffd6c52f24a..9a58e053c121d1d02e7cad32eff3024c0109fae0 100644
--- a/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp
+++ b/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp
@@ -218,9 +218,6 @@ public:
     PropertyTreeManager(cc::PropertyTrees& propertyTrees, cc::Layer* rootLayer)
         : m_propertyTrees(propertyTrees)
         , m_rootLayer(rootLayer)
-#if DCHECK_IS_ON()
-        , m_isFirstEffectEver(true)
-#endif
     {
         m_effectStack.append(BlinkEffectAndCcIdPair{nullptr, kSecondaryRootNodeId});
     }
@@ -230,7 +227,7 @@ public:
 
     int compositorIdForTransformNode(const TransformPaintPropertyNode*);
     int compositorIdForClipNode(const ClipPaintPropertyNode*);
-    int switchToEffectNode(const EffectPaintPropertyNode& nextEffect);
+    int switchToEffectNode(const EffectPaintPropertyNode* nextEffect);
     int compositorIdForCurrentEffectNode() const { return m_effectStack.last().id; }
     int compositorIdForScrollNode(const ScrollPaintPropertyNode*);
 
@@ -267,7 +264,6 @@ private:
 
 #if DCHECK_IS_ON()
     HashSet<const EffectPaintPropertyNode*> m_effectNodesConverted;
-    bool m_isFirstEffectEver;
 #endif
 };
 
@@ -435,17 +431,16 @@ const EffectPaintPropertyNode* lowestCommonAncestor(const EffectPaintPropertyNod
     return nodeA;
 }
 
-int PropertyTreeManager::switchToEffectNode(const EffectPaintPropertyNode& nextEffect)
+int PropertyTreeManager::switchToEffectNode(const EffectPaintPropertyNode* nextEffect)
 {
-    const EffectPaintPropertyNode* ancestor = lowestCommonAncestor(currentEffectNode(), &nextEffect);
+    const EffectPaintPropertyNode* ancestor = lowestCommonAncestor(currentEffectNode(), nextEffect);
     while (currentEffectNode() != ancestor)
         m_effectStack.removeLast();
 
-#if DCHECK_IS_ON()
-    DCHECK(m_isFirstEffectEver || currentEffectNode()) << "Malformed effect tree. Nodes in the same property tree should have common root.";
-    m_isFirstEffectEver = false;
-#endif
-    buildEffectNodesRecursively(&nextEffect);
+    if (!nextEffect)
+        return kSecondaryRootNodeId;
+
+    buildEffectNodesRecursively(nextEffect);
 
     return compositorIdForCurrentEffectNode();
 }
@@ -525,7 +520,7 @@ void PaintArtifactCompositor::update(const PaintArtifact& paintArtifact)
         int transformId = propertyTreeManager.compositorIdForTransformNode(paintChunk.properties.transform.get());
         int scrollId = propertyTreeManager.compositorIdForScrollNode(paintChunk.properties.scroll.get());
         int clipId = propertyTreeManager.compositorIdForClipNode(paintChunk.properties.clip.get());
-        int effectId = propertyTreeManager.switchToEffectNode(*paintChunk.properties.effect.get());
+        int effectId = propertyTreeManager.switchToEffectNode(paintChunk.properties.effect.get());
 
         propertyTreeManager.updateScrollOffset(layer->id(), scrollId);