Oilpan: Move more code of RenderObject destructors to destroy().

Source/core/rendering/RenderBlock.h

Index: Source/core/rendering/RenderBlock.h
diff --git a/Source/core/rendering/RenderBlock.h b/Source/core/rendering/RenderBlock.h
index 40c47940b6902a526078f627e7c37767c6afef18..e3028b6c4b9d83420276d2002695b5b21d7bd666 100644
--- a/Source/core/rendering/RenderBlock.h
+++ b/Source/core/rendering/RenderBlock.h
@@ -55,6 +55,7 @@ enum ContainingBlockState { NewContainingBlock, SameContainingBlock };
 
 class RenderBlock : public RenderBox {
 public:
+    virtual void destroy() OVERRIDE;
     virtual void trace(Visitor*) OVERRIDE;
     friend class LineLayoutState;
 
@@ -443,6 +444,7 @@ private:
     // End helper functions and structs used by layoutBlockChildren.
 
     bool widthAvailableToChildrenHasChanged();
+    void removeFromGlobalMaps();
 
 protected:
     // Returns the logicalOffset at the top of the next page. If the offset passed in is already at the top of the current page,