Remove some unused functions in core

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 270192a5c837587c20c34659ecd6fd18c85d2fb1..457fc1612d5cabf4ec720052e3dac9e57d8ca931 100644
--- a/Source/core/clipboard/DataObject.cpp
+++ b/Source/core/clipboard/DataObject.cpp
@@ -62,11 +62,6 @@ PassRefPtrWillBeRawPtr<DataObject> DataObject::create()
     return adoptRefWillBeNoop(new DataObject());
 }
 
-PassRefPtrWillBeRawPtr<DataObject> DataObject::copy() const
-{
-    return adoptRefWillBeNoop(new DataObject(*this));
-}
-
 DataObject::~DataObject()
 {
 }
@@ -224,12 +219,6 @@ DataObject::DataObject()
 {
 }
 
-DataObject::DataObject(const DataObject& other)
-    : m_itemList(other.m_itemList)
-    , m_modifierKeyState(0)
-{
-}
-
 PassRefPtrWillBeRawPtr<DataObjectItem> DataObject::findStringItem(const String& type) const
 {
     for (size_t i = 0; i < m_itemList.size(); ++i) {