Replace setIndexedDBClientCreateFunction madness with Supplements

third_party/WebKit/Source/web/IndexedDBClientImpl.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 17 matching lines @@
 
 #ifndef IndexedDBClientImpl_h
 #define IndexedDBClientImpl_h
 
 #include "modules/indexeddb/IndexedDBClient.h"
 
 namespace blink {
 
 class ExecutionContext;
 
 // TODO(haraken): Remove IndexedDBClientImpl.

[jsbell, 2016/04/08 19:07:02]

We can probably make comment less scary, given that this is now a common
pattern.

 // This class is used to bypass the disallowed dependency from modules/ to web/
 // to call allowIndexedDB() from modules/. ChromeClient is a mechanism to bypass
 // the dependency but we cannot use ChromeClient here because
 // IndexedDBClientImpl is used by worker threads but ChromeClient works only
 // for the main thread.
-class IndexedDBClientImpl final : public IndexedDBClient {
+class IndexedDBClientImpl final : public GarbageCollectedFinalized<IndexedDBClientImpl>, public IndexedDBClient {
+    USING_GARBAGE_COLLECTED_MIXIN(IndexedDBClientImpl);
 public:
     static IndexedDBClient* create();
 
+    ~IndexedDBClientImpl() override;
+    DECLARE_VIRTUAL_TRACE();
+
     bool allowIndexedDB(ExecutionContext*, const String& name) override;
 
 private:
-    IndexedDBClientImpl() { }
+    IndexedDBClientImpl();
 };
 
 } // namespace blink
 
 #endif // IndexedDBClientImpl_h