Store local border box property cache outside ObjectPaintProperties

third_party/WebKit/Source/core/paint/FindPropertiesNeedingUpdate.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 FindPropertiesNeedingUpdate_h
 #define FindPropertiesNeedingUpdate_h
 
 #if DCHECK_IS_ON()
 namespace blink {
 
@@ skipping 100 matching lines @@
     // No need to check if an update was already needed.
     if (m_neededPaintPropertyUpdate || m_neededForcedSubtreeUpdate)
       return;
 
     // Mark the properties as needing an update to ensure they are rebuilt.
     m_object.getMutableForPainting()
         .setOnlyThisNeedsPaintPropertyUpdateForTesting();
 
     if (const auto* properties = m_object.paintProperties())
       m_originalProperties = properties->clone();
+
+    if (const auto* localBorderBox = m_object.localBorderBoxProperties()) {
+      m_originalLocalBorderBoxProperties =
+          WTF::wrapUnique(new PropertyTreeState(*localBorderBox));
+    }
   }
 
   ~FindObjectPropertiesNeedingUpdateScope() {
     // No need to check if an update was already needed.
     if (m_neededPaintPropertyUpdate || m_neededForcedSubtreeUpdate)
       return;
 
     // If these checks fail, the paint properties changed unexpectedly. This is
     // due to missing one of these paint property invalidations:
     // 1) The LayoutObject should have been marked as needing an update with
@@ skipping 31 matching lines @@
                                 objectProperties->perspective());
       DCHECK_OBJECT_PROPERTY_EQ(
           m_object, m_originalProperties->svgLocalToBorderBoxTransform(),
           objectProperties->svgLocalToBorderBoxTransform());
       DCHECK_OBJECT_PROPERTY_EQ(m_object,
                                 m_originalProperties->scrollTranslation(),
                                 objectProperties->scrollTranslation());
       DCHECK_OBJECT_PROPERTY_EQ(m_object,
                                 m_originalProperties->scrollbarPaintOffset(),
                                 objectProperties->scrollbarPaintOffset());
-      const auto* originalBorderBox =
-          m_originalProperties->localBorderBoxProperties();
-      const auto* objectBorderBox =
-          objectProperties->localBorderBoxProperties();
-      if (originalBorderBox && objectBorderBox) {
-        DCHECK_OBJECT_PROPERTY_EQ(m_object, originalBorderBox->transform(),
-                                  objectBorderBox->transform());
-        DCHECK_OBJECT_PROPERTY_EQ(m_object, originalBorderBox->clip(),
-                                  objectBorderBox->clip());
-        DCHECK_OBJECT_PROPERTY_EQ(m_object, originalBorderBox->effect(),
-                                  objectBorderBox->effect());
-      } else {
-        DCHECK_EQ(!!originalBorderBox, !!objectBorderBox)
-            << " Object: " << m_object.debugName();
-      }
     } else {
       DCHECK_EQ(!!m_originalProperties, !!objectProperties)
           << " Object: " << m_object.debugName();
     }
+
+    const auto* objectBorderBox = m_object.localBorderBoxProperties();
+    if (m_originalLocalBorderBoxProperties && objectBorderBox) {
+      DCHECK_OBJECT_PROPERTY_EQ(m_object,
+                                m_originalLocalBorderBoxProperties->transform(),
+                                objectBorderBox->transform());
+      DCHECK_OBJECT_PROPERTY_EQ(m_object,
+                                m_originalLocalBorderBoxProperties->clip(),
+                                objectBorderBox->clip());
+      DCHECK_OBJECT_PROPERTY_EQ(m_object,
+                                m_originalLocalBorderBoxProperties->effect(),
+                                objectBorderBox->effect());
+    } else {
+      DCHECK_EQ(!!m_originalLocalBorderBoxProperties, !!objectBorderBox)
+          << " Object: " << m_object.debugName();
+    }
+
+    // Instead of checking that the contents properties are unchanged here,
+    // we check them on every access in LayoutObject::contentsProperties.
+
     // Restore original clean bit.
     m_object.getMutableForPainting().clearNeedsPaintPropertyUpdateForTesting();
   }
 
  private:
   const LayoutObject& m_object;
   bool m_neededPaintPropertyUpdate;
   bool m_neededForcedSubtreeUpdate;
   LayoutPoint m_originalPaintOffset;
   std::unique_ptr<const ObjectPaintProperties> m_originalProperties;
+  std::unique_ptr<const PropertyTreeState> m_originalLocalBorderBoxProperties;
 };
 
 }  // namespace blink
 #endif  // DCHECK_IS_ON()
 
 #endif  // FindPropertiesNeedingUpdate_h