Store local border box property cache outside ObjectPaintProperties

third_party/WebKit/Source/core/layout/LayoutObject.h

Index: third_party/WebKit/Source/core/layout/LayoutObject.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.h b/third_party/WebKit/Source/core/layout/LayoutObject.h
index 76fbc890aad22bb48e02f75c967751a2475e9bd9..f59a44bbfcd08d3f4e903cbbc8425c825ebc048f 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.h
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.h
@@ -65,6 +65,7 @@ class LayoutFlowThread;
 class LayoutGeometryMap;
 class LayoutMultiColumnSpannerPlaceholder;
 class LayoutView;
+class PropertyTreeState;
 class ObjectPaintProperties;
 class PaintInvalidationState;
 class PaintLayer;
@@ -401,10 +402,27 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
     return m_rarePaintData ? m_rarePaintData->paintProperties() : nullptr;
   }
 
+  // The complete set of property nodes that should be used as a starting point
+  // to paint this LayoutObject. See: m_localBorderBoxProperties comment.
+  const PropertyTreeState* localBorderBoxProperties() const {
+    DCHECK(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled());
+    if (m_rarePaintData)
+      return m_rarePaintData->localBorderBoxProperties();
+    return nullptr;
+  }
+
+  // The complete set of property nodes that should be used as a starting point
+  // to paint contents of this LayoutObject. See: m_contentsProperties comment.
+  const PropertyTreeState* contentsProperties() const {
+    DCHECK(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled());
+    if (m_rarePaintData)
+      return m_rarePaintData->contentsProperties();
+    return nullptr;
+  }
+
  private:
   // This is for paint-related data that is not needed on all LayoutObjects.
   // TODO(pdr): Store LayoutBoxModelObject's m_paintLayer in this structure.
-  // TODO(pdr): Store ObjectPaintProperties::LocalBorderBoxProperties here.
   class CORE_EXPORT RarePaintData {
     WTF_MAKE_NONCOPYABLE(RarePaintData);
     USING_FAST_MALLOC(RarePaintData);
@@ -418,9 +436,36 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
     }
     ObjectPaintProperties& ensurePaintProperties();
 
+    PropertyTreeState* localBorderBoxProperties() const {
+      return m_localBorderBoxProperties.get();
+    }
+
+    void clearLocalBorderBoxProperties();
+    void setLocalBorderBoxProperties(PropertyTreeState&);
+    const PropertyTreeState* contentsProperties() const;
+
    private:
     // Holds references to the paint property nodes created by this object.
     std::unique_ptr<ObjectPaintProperties> m_paintProperties;
+
+    // This is a complete set of property nodes that should be used as a
+    // starting point to paint a LayoutObject. This data is cached because some
+    // properties inherit from the containing block chain instead of the
+    // painting parent and cannot be derived in O(1) during the paint walk.
+    //
+    // For example: <div style='opacity: 0.3;'/>
+    //   The div's local border box properties would have an opacity 0.3 effect
+    //   node. Even though the div has no transform, its local border box
+    //   properties would have a transform node that points to the div's
+    //   ancestor transform space.
+    std::unique_ptr<PropertyTreeState> m_localBorderBoxProperties;
+
+    // This is the complete set of property nodes that can be used to paint the
+    // contents of this object. It is similar to m_localBorderBoxProperties but
+    // includes properties (e.g., overflow clip, scroll translation) that apply
+    // to contents. This cached value is derived from m_localBorderBoxProperties
+    // and m_paintProperties and should be invalidated when these change.
+    mutable std::unique_ptr<PropertyTreeState> m_contentsProperties;
   };
 
   RarePaintData& ensureRarePaintData();
@@ -1801,8 +1846,8 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
     FRIEND_TEST_ALL_PREFIXES(AnimationCompositorAnimationsTest,
                              canStartAnimationOnCompositorEffectSPv2);
 
-    // The following two functions can be called from PaintPropertyTreeBuilder
-    // only.
+    // The following non-const functions for ObjectPaintProperties should only
+    // be called from PaintPropertyTreeBuilder.
     ObjectPaintProperties& ensurePaintProperties() {
       return m_layoutObject.ensureRarePaintData().ensurePaintProperties();
     }
@@ -1812,6 +1857,17 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
       return nullptr;
     }
 
+    // The following non-const functions for local border box properties should
+    // only be called from PaintPropertyTreeBuilder.
+    void clearLocalBorderBoxProperties() {
+      if (auto* paintData = m_layoutObject.rarePaintData())
+        paintData->clearLocalBorderBoxProperties();
+    }
+    void setLocalBorderBoxProperties(PropertyTreeState& localBorderBox) {
+      return m_layoutObject.ensureRarePaintData().setLocalBorderBoxProperties(
+          localBorderBox);
+    }
+
     friend class LayoutObject;
     MutableForPainting(const LayoutObject& layoutObject)
         : m_layoutObject(const_cast<LayoutObject&>(layoutObject)) {}