Enable fast/images with slimming paint

Source/core/paint/TransparencyDisplayItem.h

Index: Source/core/paint/TransparencyDisplayItem.h
diff --git a/Source/core/paint/TransparencyDisplayItem.h b/Source/core/paint/TransparencyDisplayItem.h
index 290d916f0d37c830bc8643a72329522ab380c8fd..b3714796b4e43fff7a7637983e8f0af58ff50b0e 100644
--- a/Source/core/paint/TransparencyDisplayItem.h
+++ b/Source/core/paint/TransparencyDisplayItem.h
@@ -11,6 +11,8 @@
 
 namespace blink {
 
+// FIXME: Move this file to TransparencyRecorder
+
 class BeginTransparencyDisplayItem : public DisplayItem {
 public:
     BeginTransparencyDisplayItem(const RenderObject* renderer, Type type, const LayoutRect& clipRect, const WebBlendMode& blendMode, const float opacity)
@@ -44,6 +46,18 @@ private:
 #endif
 };
 
+class TransparencyRecorder {
+public:
+    explicit TransparencyRecorder(GraphicsContext*, const RenderObject*, DisplayItem::Type, const LayoutRect& clipRect, const WebBlendMode&, const float opacity);
+
+    ~TransparencyRecorder();
+
+private:
+    const RenderObject* m_renderer;
+    const DisplayItem::Type m_type;
+    GraphicsContext* m_graphicsContext;
+};
+
 } // namespace blink
 
 #endif // TransparencyDisplayItem_h