Use more unique_ptrs in CPDF_Image.

core/fpdfapi/page/cpdf_formobject.cpp

Index: core/fpdfapi/page/cpdf_formobject.cpp
diff --git a/core/fpdfapi/page/cpdf_formobject.cpp b/core/fpdfapi/page/cpdf_formobject.cpp
index dd3c2c203686d4b308de4ae7c4aa662564b76234..dc596e53c64ab4f3ac234d50a4874a6009a372d4 100644
--- a/core/fpdfapi/page/cpdf_formobject.cpp
+++ b/core/fpdfapi/page/cpdf_formobject.cpp
@@ -29,15 +29,6 @@ const CPDF_FormObject* CPDF_FormObject::AsForm() const {
   return this;
 }
 
-CPDF_FormObject* CPDF_FormObject::Clone() const {
-  CPDF_FormObject* obj = new CPDF_FormObject;
-  obj->CopyData(this);
-
-  obj->m_pForm.reset(m_pForm->Clone());
-  obj->m_FormMatrix = m_FormMatrix;
-  return obj;
-}
-
 CPDF_PageObject::Type CPDF_FormObject::GetType() const {
   return FORM;
 }