Add WebDataConsumerHandle::debugName()

public/platform/WebDataConsumerHandle.h

 // Copyright 2014 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 WebDataConsumerHandle_h
 #define WebDataConsumerHandle_h
 
 #include <stddef.h>
 
 #if INSIDE_BLINK
@@ skipping 95 matching lines @@
     // handle is not locked. |client| can be null. Otherwise, |*client| must be
     // valid as long as the reader is valid. The returned reader is bound to
     // the calling thread and client notification will be called on the thread
     // if |client| is not null.
     // If |client| is not null and the handle is not waiting, client
     // notification is called asynchronously.
 #if INSIDE_BLINK
     PassOwnPtr<Reader> obtainReader(Client* client) { return adoptPtr(obtainReaderInternal(client)); }
 #endif
 
+    // Returns a string literal (e.g. class name) for debugging only.
+    virtual const char* debugName() const { return "WebDataConsumerHandle"; }
+
 private:
     // The caller takes ownership of the returned object.
     virtual Reader* obtainReaderInternal(Client* client)
     {
         BLINK_ASSERT_NOT_REACHED();
         return nullptr;
     }
 
     // Below are deprecated functions that will be removed shortly. Use Reader
     // instead.
@@ skipping 25 matching lines @@
     // Only one registration can be made for a handle at a time.
     virtual void registerClient(Client* /* client */)  { }
 
     // Unregisters |client| from this handle.
     virtual void unregisterClient() { }
 };
 
 } // namespace blink
 
 #endif // WebDataConsumerHandle_h