Implement the algorithm to test merging and overlap in PaintArtifactCompositor.

third_party/WebKit/Source/platform/graphics/paint/TransformPaintPropertyNode.h

 // Copyright 2015 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.
 
 #ifndef TransformPaintPropertyNode_h
 #define TransformPaintPropertyNode_h
 
 #include "platform/PlatformExport.h"
 #include "platform/geometry/FloatPoint3D.h"
+#include "platform/graphics/CompositingReasons.h"
 #include "platform/transforms/TransformationMatrix.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 
 #include <iosfwd>
 
 namespace blink {
 
 // A transform created by a css property such as "transform" or "perspective"
 // along with a reference to the parent TransformPaintPropertyNode.
 //
 // The transform tree is rooted at a node with no parent. This root node should
 // not be modified.
 class PLATFORM_EXPORT TransformPaintPropertyNode
     : public RefCounted<TransformPaintPropertyNode> {
  public:
   static TransformPaintPropertyNode* root();
 
   static PassRefPtr<TransformPaintPropertyNode> create(
       PassRefPtr<const TransformPaintPropertyNode> parent,
       const TransformationMatrix& matrix,
       const FloatPoint3D& origin,
       bool flattensInheritedTransform = false,
-      unsigned renderingContextID = 0) {
+      unsigned renderingContextID = 0,
+      CompositingReasons directCompositingReasons = CompositingReasonNone) {
     return adoptRef(new TransformPaintPropertyNode(
         matrix, origin, std::move(parent), flattensInheritedTransform,
-        renderingContextID));
+        renderingContextID, directCompositingReasons));
   }
 
-  void update(PassRefPtr<const TransformPaintPropertyNode> parent,
-              const TransformationMatrix& matrix,
-              const FloatPoint3D& origin,
-              bool flattensInheritedTransform = false,
-              unsigned renderingContextID = 0) {
+  void update(
+      PassRefPtr<const TransformPaintPropertyNode> parent,
+      const TransformationMatrix& matrix,
+      const FloatPoint3D& origin,
+      bool flattensInheritedTransform = false,
+      unsigned renderingContextID = 0,
+      CompositingReasons directCompositingReasons = CompositingReasonNone) {
     DCHECK(!isRoot());
     DCHECK(parent != this);
     m_parent = parent;
     m_matrix = matrix;
     m_origin = origin;
     m_flattensInheritedTransform = flattensInheritedTransform;
     m_renderingContextID = renderingContextID;
+    m_directCompositingReasons = directCompositingReasons;
   }
 
   const TransformationMatrix& matrix() const { return m_matrix; }
   const FloatPoint3D& origin() const { return m_origin; }
 
   // Parent transform that this transform is relative to, or nullptr if this
   // is the root transform.
   const TransformPaintPropertyNode* parent() const { return m_parent.get(); }
   bool isRoot() const { return !m_parent; }
 
   // If true, content with this transform node (or its descendant) appears in
   // the plane of its parent. This is implemented by flattening the total
   // accumulated transform from its ancestors.
   bool flattensInheritedTransform() const {
     return m_flattensInheritedTransform;
   }
 
   // Content whose transform nodes have a common rendering context ID are 3D
   // sorted. If this is 0, content will not be 3D sorted.
   unsigned renderingContextID() const { return m_renderingContextID; }
   bool hasRenderingContext() const { return m_renderingContextID; }
 
+  bool hasDirectCompositingReasons() const {
+    return m_directCompositingReasons != CompositingReasonNone;
+  }
+
 #if DCHECK_IS_ON()
   // The clone function is used by FindPropertiesNeedingUpdate.h for recording
   // a transform node before it has been updated, to later detect changes.
   PassRefPtr<TransformPaintPropertyNode> clone() const {
-    return adoptRef(new TransformPaintPropertyNode(m_matrix, m_origin, m_parent,
-                                                   m_flattensInheritedTransform,
-                                                   m_renderingContextID));
+    return adoptRef(new TransformPaintPropertyNode(
+        m_matrix, m_origin, m_parent, m_flattensInheritedTransform,
+        m_renderingContextID, m_directCompositingReasons));
   }
 
   // The equality operator is used by FindPropertiesNeedingUpdate.h for checking
   // if a transform node has changed.
   bool operator==(const TransformPaintPropertyNode& o) const {
     return m_matrix == o.m_matrix && m_origin == o.m_origin &&
            m_parent == o.m_parent &&
            m_flattensInheritedTransform == o.m_flattensInheritedTransform &&
            m_renderingContextID == o.m_renderingContextID;
   }
 #endif
 
  private:
   TransformPaintPropertyNode(
       const TransformationMatrix& matrix,
       const FloatPoint3D& origin,
       PassRefPtr<const TransformPaintPropertyNode> parent,
       bool flattensInheritedTransform,
-      unsigned renderingContextID)
+      unsigned renderingContextID,
+      CompositingReasons directCompositingReasons)
       : m_matrix(matrix),
         m_origin(origin),
         m_parent(parent),
         m_flattensInheritedTransform(flattensInheritedTransform),
-        m_renderingContextID(renderingContextID) {}
+        m_renderingContextID(renderingContextID),
+        m_directCompositingReasons(directCompositingReasons) {}
 
   TransformationMatrix m_matrix;
   FloatPoint3D m_origin;
   RefPtr<const TransformPaintPropertyNode> m_parent;
   bool m_flattensInheritedTransform;
   unsigned m_renderingContextID;
+  CompositingReasons m_directCompositingReasons;
 };
 
 // Redeclared here to avoid ODR issues.
 // See platform/testing/PaintPrinters.h.
 void PrintTo(const TransformPaintPropertyNode&, std::ostream*);
 
 }  // namespace blink
 
 #endif  // TransformPaintPropertyNode_h