Remove some unused functions in core

Source/core/clipboard/DataTransfer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 361 matching lines @@
 
     String str = text;
 #if OS(WIN)
     replaceNewlinesWithWindowsStyleNewlines(str);
 #endif
     replaceNBSPWithSpace(str);
 
     m_dataObject->setData(mimeTypeTextPlain, str);
 }
 
-bool DataTransfer::hasData()
-{
-    ASSERT(isForDragAndDrop());
-
-    return m_dataObject->length() > 0;
-}
-
 void DataTransfer::setAccessPolicy(DataTransferAccessPolicy policy)
 {
     // once you go numb, can never go back
     ASSERT(m_policy != DataTransferNumb || policy == DataTransferNumb);
     m_policy = policy;
 }
 
 bool DataTransfer::canReadTypes() const
 {
     return m_policy == DataTransferReadable || m_policy == DataTransferTypesReadable || m_policy == DataTransferWritable;
@@ skipping 132 matching lines @@
     }
 }
 
 void DataTransfer::trace(Visitor* visitor)
 {
     visitor->trace(m_dataObject);
     visitor->trace(m_dragImageElement);
 }
 
 } // namespace blink