Remove more dead code from core/ folder

Source/core/clipboard/DataObject.cpp

 /*
  * Copyright (c) 2008, 2009, 2012 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 106 matching lines @@
 {
     for (size_t i = 0; i < m_itemList.size(); ++i) {
         if (m_itemList[i]->kind() == DataObjectItem::StringKind && m_itemList[i]->type() == type) {
             // Per the spec, type must be unique among all items of kind 'string'.
             m_itemList.remove(i);
             return;
         }
     }
 }
 
-void DataObject::clearAllExceptFiles()
-{
-    for (size_t i = 0; i < m_itemList.size(); ) {
-        if (m_itemList[i]->kind() != DataObjectItem::FileKind) {
-            m_itemList.remove(i);
-            continue;
-        }
-        ++i;
-    }
-}
-
 ListHashSet<String> DataObject::types() const
 {
     ListHashSet<String> results;
     bool containsFiles = false;
     for (size_t i = 0; i < m_itemList.size(); ++i) {
         switch (m_itemList[i]->kind()) {
         case DataObjectItem::StringKind:
             results.add(m_itemList[i]->type());
             break;
         case DataObjectItem::FileKind:
@@ skipping 121 matching lines @@
     m_itemList.append(item);
 }
 
 void DataObject::trace(Visitor* visitor)
 {
     visitor->trace(m_itemList);
     WillBeHeapSupplementable<DataObject>::trace(visitor);
 }
 
 } // namespace WebCore