Move scroll paint property nodes to be owned by the transform tree

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

 // 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.
 
 #ifndef PropertyTreeState_h
 #define PropertyTreeState_h
 
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/EffectPaintPropertyNode.h"
-#include "platform/graphics/paint/ScrollPaintPropertyNode.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "wtf/HashFunctions.h"
 #include "wtf/HashTraits.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 // A complete set of paint properties including those that are inherited from
 // other objects.  RefPtrs are used to guard against use-after-free bugs and
 // DCHECKs ensure PropertyTreeState never retains the last reference to a
 // property tree node.
 class PLATFORM_EXPORT PropertyTreeState {
  public:
   PropertyTreeState(const TransformPaintPropertyNode* transform,
                     const ClipPaintPropertyNode* clip,
-                    const EffectPaintPropertyNode* effect,
-                    const ScrollPaintPropertyNode* scroll)
-      : m_transform(transform),
-        m_clip(clip),
-        m_effect(effect),
-        m_scroll(scroll) {
+                    const EffectPaintPropertyNode* effect)
+      : m_transform(transform), m_clip(clip), m_effect(effect) {
     DCHECK(!m_transform || !m_transform->hasOneRef());
     DCHECK(!m_clip || !m_clip->hasOneRef());
     DCHECK(!m_effect || !m_effect->hasOneRef());
-    DCHECK(!m_scroll || !m_scroll->hasOneRef());
   }
 
   bool hasDirectCompositingReasons() const;
 
   const TransformPaintPropertyNode* transform() const {
     DCHECK(!m_transform || !m_transform->hasOneRef());
     return m_transform.get();
   }
   void setTransform(RefPtr<const TransformPaintPropertyNode> node) {
     m_transform = std::move(node);
   }
 
   const ClipPaintPropertyNode* clip() const {
     DCHECK(!m_clip || !m_clip->hasOneRef());
     return m_clip.get();
   }
   void setClip(RefPtr<const ClipPaintPropertyNode> node) {
     m_clip = std::move(node);
   }
 
   const EffectPaintPropertyNode* effect() const {
     DCHECK(!m_effect || !m_effect->hasOneRef());
     return m_effect.get();
   }
   void setEffect(RefPtr<const EffectPaintPropertyNode> node) {
     m_effect = std::move(node);
   }
 
-  const ScrollPaintPropertyNode* scroll() const {
-    DCHECK(!m_scroll || !m_scroll->hasOneRef());
-    return m_scroll.get();
-  }
-  void setScroll(RefPtr<const ScrollPaintPropertyNode> node) {
-    m_scroll = std::move(node);
-  }
-
-  // Returns the compositor element id, if any, for this property state. If none
-  // of the scroll, effect or transform nodes for this state have a compositor
-  // element id then a default instance is returned.
+  // Returns the compositor element id, if any, for this property state. If
+  // neither the effect nor transform nodes have a compositor element id then a
+  // default instance is returned.
   const CompositorElementId compositorElementId() const;
 
   enum InnermostNode {
     None,  // None means that all nodes are their root values
     Transform,
     Clip,
     Effect,
   };
 
   // There is always a well-defined order in which the transform, clip
@@ skipping 35 matching lines @@
 
 #if DCHECK_IS_ON()
   // Dumps the tree from this state up to the root as a string.
   String toTreeString() const;
 #endif
 
  private:
   RefPtr<const TransformPaintPropertyNode> m_transform;
   RefPtr<const ClipPaintPropertyNode> m_clip;
   RefPtr<const EffectPaintPropertyNode> m_effect;
-  // TODO(pdr): Remove the scroll node from PropertyTreeState.
-  RefPtr<const ScrollPaintPropertyNode> m_scroll;
 };
 
 inline bool operator==(const PropertyTreeState& a, const PropertyTreeState& b) {
   return a.transform() == b.transform() && a.clip() == b.clip() &&
-         a.effect() == b.effect() && a.scroll() == b.scroll();
+         a.effect() == b.effect();
 }
 
 // Iterates over the sequence transforms, clips and effects for a
 // PropertyTreeState between that state and the "root" state (all nodes equal
 // to *::Root()), in the order that they apply.
 //
 // See also PropertyTreeState::innermostNode for a more detailed example.
 class PLATFORM_EXPORT PropertyTreeStateIterator {
  public:
   PropertyTreeStateIterator(const PropertyTreeState& properties)
@@ skipping 45 matching lines @@
   }
 
   HashMap<const PropertyTreeNode*, String> m_nodeToDebugString;
 };
 
 #endif
 
 }  // namespace blink
 
 #endif  // PropertyTreeState_h