(Reland) Add effect node support in PaintArtifactCompositor for layer list mode [4/4]

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 7f85e9e41bada787a6089cace5c8d3f2af7c6881..5e552c2b831d41bcbec65d4804ad153d25362798 100644
--- a/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp
+++ b/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp
@@ -345,14 +345,27 @@ class PropertyTreeManager {
 public:
     PropertyTreeManager(cc::PropertyTrees& propertyTrees, cc::Layer* rootLayer)
         : m_propertyTrees(propertyTrees)
-        , m_rootLayer(rootLayer) {}
+        , m_rootLayer(rootLayer)
+#if DCHECK_IS_ON()
+        , m_isFirstEffectEver(true)
+#endif
+    {
+        m_effectStack.append(BlinkEffectAndCcIdPair{nullptr, kSecondaryRootNodeId});
+    }
 
     int compositorIdForTransformNode(const TransformPaintPropertyNode*);
     int compositorIdForClipNode(const ClipPaintPropertyNode*);
+    int switchToEffectNode(const EffectPaintPropertyNode& nextEffect);
+    int compositorIdForCurrentEffectNode() const { return m_effectStack.last().id; }
 
 private:
+    void buildEffectNodesRecursively(const EffectPaintPropertyNode* nextEffect);
+
     cc::TransformTree& transformTree() { return m_propertyTrees.transform_tree; }
     cc::ClipTree& clipTree() { return m_propertyTrees.clip_tree; }
+    cc::EffectTree& effectTree() { return m_propertyTrees.effect_tree; }
+
+    const EffectPaintPropertyNode* currentEffectNode() const { return m_effectStack.last().effect; }
 
     // Property trees which should be updated by the manager.
     cc::PropertyTrees& m_propertyTrees;
@@ -364,6 +377,17 @@ private:
     // Maps from Blink-side property tree nodes to cc property node indices.
     HashMap<const TransformPaintPropertyNode*, int> m_transformNodeMap;
     HashMap<const ClipPaintPropertyNode*, int> m_clipNodeMap;
+
+    struct BlinkEffectAndCcIdPair {
+        const EffectPaintPropertyNode* effect;
+        int id;
+    };
+    Vector<BlinkEffectAndCcIdPair> m_effectStack;
+
+#if DCHECK_IS_ON()
+    HashSet<const EffectPaintPropertyNode*> m_effectNodesConverted;
+    bool m_isFirstEffectEver;
+#endif
 };
 
 int PropertyTreeManager::compositorIdForTransformNode(const TransformPaintPropertyNode* transformNode)
@@ -442,6 +466,91 @@ int PropertyTreeManager::compositorIdForClipNode(const ClipPaintPropertyNode* cl
     return id;
 }
 
+unsigned depth(const EffectPaintPropertyNode* node)
+{
+    unsigned result = 0;
+    for (; node; node = node->parent())
+        result++;
+    return result;
+}
+
+const EffectPaintPropertyNode* lowestCommonAncestor(const EffectPaintPropertyNode* nodeA, const EffectPaintPropertyNode* nodeB)
+{
+    // Optimized common case.
+    if (nodeA == nodeB)
+        return nodeA;
+
+    unsigned depthA = depth(nodeA), depthB = depth(nodeB);
+    while (depthA > depthB) {
+        nodeA = nodeA->parent();
+        depthA--;
+    }
+    while (depthB > depthA) {
+        nodeB = nodeB->parent();
+        depthB--;
+    }
+    DCHECK_EQ(depthA, depthB);
+    while (nodeA != nodeB) {
+        nodeA = nodeA->parent();
+        nodeB = nodeB->parent();
+    }
+    return nodeA;
+}
+
+int PropertyTreeManager::switchToEffectNode(const EffectPaintPropertyNode& 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);
+
+    return compositorIdForCurrentEffectNode();
+}
+
+void PropertyTreeManager::buildEffectNodesRecursively(const EffectPaintPropertyNode* nextEffect)
+{
+    if (nextEffect == currentEffectNode())
+        return;
+    DCHECK(nextEffect);
+
+    buildEffectNodesRecursively(nextEffect->parent());
+    DCHECK_EQ(nextEffect->parent(), currentEffectNode());
+
+#if DCHECK_IS_ON()
+    DCHECK(!m_effectNodesConverted.contains(nextEffect)) << "Malformed paint artifact. Paint chunks under the same effect should be contiguous.";
+    m_effectNodesConverted.add(nextEffect);
+#endif
+
+    // We currently create dummy layers to host effect nodes and corresponding render surface.
+    // This should be removed once cc implements better support for freestanding property trees.
+    scoped_refptr<cc::Layer> dummyLayer = cc::Layer::Create();
+    m_rootLayer->AddChild(dummyLayer);
+
+    // Also cc assumes a clip node is always created by a layer that creates render surface.
+    cc::ClipNode& dummyClip = *clipTree().Node(clipTree().Insert(cc::ClipNode(), kSecondaryRootNodeId));
+    dummyClip.owner_id = dummyLayer->id();
+    dummyClip.transform_id = kRealRootNodeId;
+    dummyClip.target_transform_id = kRealRootNodeId;
+
+    cc::EffectNode& effectNode = *effectTree().Node(effectTree().Insert(cc::EffectNode(), compositorIdForCurrentEffectNode()));
+    effectNode.owner_id = dummyLayer->id();
+    effectNode.clip_id = dummyClip.id;
+    effectNode.has_render_surface = true;
+    effectNode.opacity = nextEffect->opacity();
+    m_effectStack.append(BlinkEffectAndCcIdPair{nextEffect, effectNode.id});
+
+    dummyLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
+    dummyLayer->SetTransformTreeIndex(kSecondaryRootNodeId);
+    dummyLayer->SetClipTreeIndex(dummyClip.id);
+    dummyLayer->SetEffectTreeIndex(effectNode.id);
+    dummyLayer->SetScrollTreeIndex(kRealRootNodeId);
+}
+
 } // namespace
 
 void PaintArtifactCompositor::updateInLayerListMode(const PaintArtifact& paintArtifact)
@@ -465,6 +574,7 @@ void PaintArtifactCompositor::updateInLayerListMode(const PaintArtifact& paintAr
 
         int transformId = propertyTreeManager.compositorIdForTransformNode(paintChunk.properties.transform.get());
         int clipId = propertyTreeManager.compositorIdForClipNode(paintChunk.properties.clip.get());
+        int effectId = propertyTreeManager.switchToEffectNode(*paintChunk.properties.effect.get());
 
         layer->set_offset_to_transform_parent(layerOffset);
 
@@ -472,7 +582,7 @@ void PaintArtifactCompositor::updateInLayerListMode(const PaintArtifact& paintAr
         layer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
         layer->SetTransformTreeIndex(transformId);
         layer->SetClipTreeIndex(clipId);
-        layer->SetEffectTreeIndex(kSecondaryRootNodeId);
+        layer->SetEffectTreeIndex(effectId);
         layer->SetScrollTreeIndex(kRealRootNodeId);
 
         if (m_extraDataForTestingEnabled)