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

Source/platform/graphics/paint/DrawingRecorder.h

Index: Source/platform/graphics/paint/DrawingRecorder.h
diff --git a/Source/platform/graphics/paint/DrawingRecorder.h b/Source/platform/graphics/paint/DrawingRecorder.h
index 2d399a65197d52aa81166690650d6defc74b98d9..be4f32bd0aae914c89074f2d5ebee5fc00c26945 100644
--- a/Source/platform/graphics/paint/DrawingRecorder.h
+++ b/Source/platform/graphics/paint/DrawingRecorder.h
@@ -20,9 +20,12 @@ class GraphicsContext;
 
 class PLATFORM_EXPORT DrawingRecorder {
 public:
+    DrawingRecorder(GraphicsContext&, const DisplayItemClientWrapper&, DisplayItem::Type);
     DrawingRecorder(GraphicsContext&, const DisplayItemClientWrapper&, DisplayItem::Type, const FloatRect& cullRect);
     ~DrawingRecorder();
 
+    void begin(const FloatRect& cullRect);
+
     bool canUseCachedDrawing() const
     {
 #if ENABLE(ASSERT)
@@ -40,6 +43,7 @@ private:
     DisplayItemClientWrapper m_displayItemClient;
     const DisplayItem::Type m_displayItemType;
     bool m_canUseCachedDrawing;
+    bool m_engaged;
 #if ENABLE(ASSERT)
     mutable bool m_checkedCachedDrawing;
     size_t m_displayItemPosition;