Add infrastructure for partial layouts

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 689e36c6d1ee9f8e74c2ddc80717147a26099333..1e086f16a89080a1c62c36b1f118b43ba9346fec 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -739,6 +739,12 @@ void RenderObject::checkBlockPositionedObjectsNeedLayout()
     if (isRenderBlock())
         toRenderBlock(this)->checkPositionedObjectsNeedLayout();
 }
+
+void RenderObject::checkNotInPartialLayout()
+{
+    // During partial layout, setNeedsLayout(true or false) should not be called.
+    ASSERT(!frameView()->partialLayout().shouldStop());
+}
 #endif
 
 void RenderObject::setPreferredLogicalWidthsDirty(MarkingBehavior markParents)
@@ -2768,6 +2774,11 @@ bool RenderObject::nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitT
     return false;
 }
 
+FrameView* RenderObject::frameView() const
+{
+    return document().view();
+}
+
 void RenderObject::scheduleRelayout()
 {
     if (isRenderView()) {