Show debug information for invalid display items

Source/platform/graphics/ContiguousContainer.h

Index: Source/platform/graphics/ContiguousContainer.h
diff --git a/Source/platform/graphics/ContiguousContainer.h b/Source/platform/graphics/ContiguousContainer.h
index bfea148e71b3ae6616d8fd4c9b1a6d374b7015b6..547a132ce73bf129e447197e41a3db694d7fca23 100644
--- a/Source/platform/graphics/ContiguousContainer.h
+++ b/Source/platform/graphics/ContiguousContainer.h
@@ -176,7 +176,11 @@ public:
         ASSERT(size >= sizeof(BaseElementType));
         void* newItem = allocate(size);
         memcpy(newItem, static_cast<void*>(&item), size);
-        new (&item) BaseElementType;
+        new (&item) BaseElementType(
+#ifndef NDEBUG
+            item.asDebugString()
+#endif
+        );
         return *static_cast<BaseElementType*>(newItem);
     }