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 1e4bafeefd26e7c2ed9d567bbe1cb546712e22eb..428067ea616f41297934097b50e1ef319a6db815 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -750,6 +750,16 @@ void RenderObject::checkBlockPositionedObjectsNeedLayout()
     if (isRenderBlock())
         toRenderBlock(this)->checkPositionedObjectsNeedLayout();
 }
+
+void RenderObject::checkNotInPartialLayout()
+{
+    if (frame()) {
+        if (FrameView* view = frame()->view()) {
+            // During partial layout, setNeedsLayout(true or false) should not be called.
+            ASSERT(!view->shouldStopPartialLayout());
+        }
+    }
+}
 #endif
 
 void RenderObject::setPreferredLogicalWidthsDirty(bool shouldBeDirty, MarkingBehavior markParents)