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

Source/core/paint/FloatClipRecorder.h

Index: Source/core/paint/FloatClipRecorder.h
diff --git a/Source/core/paint/FloatClipRecorder.h b/Source/core/paint/FloatClipRecorder.h
index 830d5621d39e800dc1e2fa981df0128e5eb4ef76..705c7f856ac03ef5733b3b46ac1d3abbe30c0869 100644
--- a/Source/core/paint/FloatClipRecorder.h
+++ b/Source/core/paint/FloatClipRecorder.h
@@ -13,14 +13,17 @@ namespace blink {
 
 class FloatClipRecorder {
 public:
+    FloatClipRecorder(GraphicsContext&, const DisplayItemClientWrapper&, PaintPhase);
     FloatClipRecorder(GraphicsContext&, const DisplayItemClientWrapper&, PaintPhase, const FloatRect&);
-
     ~FloatClipRecorder();
 
+    void begin(const FloatRect&);
+
 private:
     GraphicsContext& m_context;
     DisplayItemClientWrapper m_client;
     DisplayItem::Type m_clipType;
+    bool m_engaged;
 };
 
 } // namespace blink