Preliminary paint property walk implementation for SPv2

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

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 33ebe5d70e5514d82cfa6dbdc943c3469146d4cd..aa4cc213a26879f3e99edea5b3cd3979168cd56f 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -74,6 +74,7 @@
 #include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/Page.h"
+#include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/ObjectPainter.h"
 #include "core/paint/PaintInfo.h"
 #include "core/paint/PaintLayer.h"
@@ -148,6 +149,15 @@ bool LayoutObject::s_affectsParentBlock = false;
 typedef HashMap<const LayoutObject*, LayoutRect> SelectionPaintInvalidationMap;
 static SelectionPaintInvalidationMap* selectionPaintInvalidationMap = nullptr;
 
+// The pointer to paint properties is implemented as a global hash map temporarily,
+// to avoid memory regression during the transition towards SPv2.
+typedef HashMap<const LayoutObject*, OwnPtr<ObjectPaintProperties>> ObjectPaintPropertiesMap;
+static ObjectPaintPropertiesMap& objectPaintPropertiesMap()
+{
+    DEFINE_STATIC_LOCAL(ObjectPaintPropertiesMap, staticObjectPaintPropertiesMap, ());
+    return staticObjectPaintPropertiesMap;
+}
+
 void* LayoutObject::operator new(size_t sz)
 {
     ASSERT(isMainThread());
@@ -2513,6 +2523,9 @@ void LayoutObject::willBeDestroyed()
     if (selectionPaintInvalidationMap)
         selectionPaintInvalidationMap->remove(this);
 
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+        clearObjectPaintProperties();
+
     clearLayoutRootIfNeeded();
 
     if (m_style) {
@@ -3458,6 +3471,26 @@ void LayoutObject::setIsBackgroundAttachmentFixedObject(bool isBackgroundAttachm
         frameView()->removeBackgroundAttachmentFixedObject(this);
 }
 
+ObjectPaintProperties* LayoutObject::objectPaintProperties() const
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
+    return objectPaintPropertiesMap().get(this);
+}
+
+ObjectPaintProperties& LayoutObject::ensureObjectPaintProperties()
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
+    if (ObjectPaintProperties* properties = objectPaintProperties())
+        return *properties;
+    return *objectPaintPropertiesMap().set(this, ObjectPaintProperties::create()).storedValue->value.get();
+}
+
+void LayoutObject::clearObjectPaintProperties()
+{
+    ASSERT(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
+    objectPaintPropertiesMap().remove(this);
+}
+
 } // namespace blink
 
 #ifndef NDEBUG