Remove more dead code from core/ folder

Source/core/clipboard/DataObject.cpp

Index: Source/core/clipboard/DataObject.cpp
diff --git a/Source/core/clipboard/DataObject.cpp b/Source/core/clipboard/DataObject.cpp
index e904f89d9e290fbae463d49d80b37014efd1c28e..671af3d4e627cfc13ec626139551c90a8b6c8cd8 100644
--- a/Source/core/clipboard/DataObject.cpp
+++ b/Source/core/clipboard/DataObject.cpp
@@ -124,17 +124,6 @@ void DataObject::clearData(const String& type)
     }
 }
 
-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;