Allow certain SP recorder classes to defer their "begin" operation.

Source/core/paint/ScopeRecorder.h

Index: Source/core/paint/ScopeRecorder.h
diff --git a/Source/core/paint/ScopeRecorder.h b/Source/core/paint/ScopeRecorder.h
index ac7dccc2fceec6ff3bf4f59cde042a179b7c6832..af8b380686e910d5d0d29653fe5df5bbd0861c44 100644
--- a/Source/core/paint/ScopeRecorder.h
+++ b/Source/core/paint/ScopeRecorder.h
@@ -15,12 +15,16 @@ class LayoutObject;
 
 class ScopeRecorder {
 public:
-    ScopeRecorder(GraphicsContext&, const LayoutObject&);
+    enum ShouldBegin { BeginOnConstruction, DeferBegin };
+    ScopeRecorder(GraphicsContext&, const LayoutObject&, ShouldBegin = BeginOnConstruction);
     ~ScopeRecorder();
 
+    void begin();
+
 private:
     DisplayItemList* m_displayItemList;
     const LayoutObject& m_object;
+    bool m_engaged;
 };
 
 } // namespace blink