Oilpan: Prepare to move RenderObject and RenderObjectChildList to Oilpan heap.

Source/core/rendering/RenderFrameSet.cpp

Index: Source/core/rendering/RenderFrameSet.cpp
diff --git a/Source/core/rendering/RenderFrameSet.cpp b/Source/core/rendering/RenderFrameSet.cpp
index a25be209377472383c1018f61d97b9e77aa5067d..8711d0b165f67d00d66a3e259140f83ab8b8e8af 100644
--- a/Source/core/rendering/RenderFrameSet.cpp
+++ b/Source/core/rendering/RenderFrameSet.cpp
@@ -51,6 +51,12 @@ RenderFrameSet::~RenderFrameSet()
 {
 }
 
+void RenderFrameSet::trace(Visitor* visitor)
+{
+    visitor->trace(m_children);
+    RenderBox::trace(visitor);
+}
+
 RenderFrameSet::GridAxis::GridAxis()
     : m_splitBeingResized(noSplit)
 {