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 d2546bc4f140db4e6785cf78f8a963e6e3119832..9eda8eef2fa9fd5c52d55903dc6b7966fd858571 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -746,6 +746,12 @@ 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(bool shouldBeDirty, MarkingBehavior markParents)
@@ -2777,6 +2783,11 @@ bool RenderObject::nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitT
     return false;
 }
 
+FrameView* RenderObject::frameView() const
+{
+    return document()->view();
+}
+
 void RenderObject::scheduleRelayout()
 {
     if (isRenderView()) {