Implement debugName() in WebDataConsumerHandle subclasses in Blink

Source/modules/fetch/CompositeDataConsumerHandle.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CompositeDataConsumerHandle_h
 #define CompositeDataConsumerHandle_h
 
 #include "public/platform/WebDataConsumerHandle.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
@@ skipping 16 matching lines @@
 
     // This function should be called on the thread on which this object
     // was created. |handle| must not be null and must not be locked.
     void update(PassOwnPtr<WebDataConsumerHandle> /* handle */);
 
 private:
     class Context;
     class ReaderImpl;
     Reader* obtainReaderInternal(Client*) override;
 
+    const char* debugName() const override { return "CompositeDataConsumerHandle"; }
+
     explicit CompositeDataConsumerHandle(PassOwnPtr<WebDataConsumerHandle>);
 
     RefPtr<Context> m_context;
 };
 
 } // namespace blink
 
 #endif // CompositeDataConsumerHandle_h