Emit dummy display item when recorded picture is empty

Source/platform/graphics/paint/TransformDisplayItem.h

Index: Source/platform/graphics/paint/TransformDisplayItem.h
diff --git a/Source/platform/graphics/paint/TransformDisplayItem.h b/Source/platform/graphics/paint/TransformDisplayItem.h
index b138cc5fc061195f197f15f8ac3a29aada9430bd..aeb762da7f64bd9326814bf9c97bc95471ed4227 100644
--- a/Source/platform/graphics/paint/TransformDisplayItem.h
+++ b/Source/platform/graphics/paint/TransformDisplayItem.h
@@ -24,6 +24,10 @@ protected:
     BeginTransformDisplayItem(DisplayItemClient, const TransformationMatrix&);
 
 private:
+#ifndef NDEBUG
+    virtual const char* name() const override { return "BeginTransform"; }
+#endif
+
     const TransformationMatrix m_transform;
 };
 
@@ -37,6 +41,11 @@ public:
 protected:
     EndTransformDisplayItem(DisplayItemClient client)
         : DisplayItem(client, EndTransform) { }
+
+private:
+#ifndef NDEBUG
+    virtual const char* name() const override { return "EndTransform"; }
+#endif
 };
 
 } // namespace blink