Pass implementation object to supplemental classes by reference

Source/modules/indexeddb/PageGroupIndexedDatabase.cpp

Index: Source/modules/indexeddb/PageGroupIndexedDatabase.cpp
diff --git a/Source/modules/indexeddb/PageGroupIndexedDatabase.cpp b/Source/modules/indexeddb/PageGroupIndexedDatabase.cpp
index 81c0be5e03d7085701f98b55b10cbfd1183627a7..40502ffa6dcbfd809aa53e280174f4ec85e09c3b 100644
--- a/Source/modules/indexeddb/PageGroupIndexedDatabase.cpp
+++ b/Source/modules/indexeddb/PageGroupIndexedDatabase.cpp
@@ -44,14 +44,14 @@ const char* PageGroupIndexedDatabase::supplementName()
     return "PageGroupIndexedDatabase";
 }
 
-PageGroupIndexedDatabase* PageGroupIndexedDatabase::from(PageGroup& group)
+PageGroupIndexedDatabase& PageGroupIndexedDatabase::from(PageGroup& group)
 {
-    PageGroupIndexedDatabase* supplement = static_cast<PageGroupIndexedDatabase*>(Supplement<PageGroup>::from(&group, supplementName()));
+    PageGroupIndexedDatabase* supplement = static_cast<PageGroupIndexedDatabase*>(Supplement<PageGroup>::from(group, supplementName()));
     if (!supplement) {
         supplement = new PageGroupIndexedDatabase();
-        provideTo(&group, supplementName(), adoptPtr(supplement));
+        provideTo(group, supplementName(), adoptPtr(supplement));
     }
-    return supplement;
+    return *supplement;
 }
 
 IDBFactoryBackendInterface* PageGroupIndexedDatabase::factoryBackend()