Ensure CPDF_CountedObjects only made from owned references.

core/fpdfapi/page/cpdf_countedobject.h

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_FPDFAPI_PAGE_CPDF_COUNTEDOBJECT_H_
 #define CORE_FPDFAPI_PAGE_CPDF_COUNTEDOBJECT_H_
 
+#include <memory>
+
 #include "core/fpdfapi/page/cpdf_colorspace.h"
 #include "core/fpdfapi/page/cpdf_pattern.h"
 #include "core/fxcrt/fx_system.h"
 
 template <class T>
 class CPDF_CountedObject {
  public:
-  explicit CPDF_CountedObject(T* ptr) : m_nCount(1), m_pObj(ptr) {}
-  void reset(T* ptr) {  // CAUTION: tosses prior ref counts.
+  explicit CPDF_CountedObject(std::unique_ptr<T> ptr)
+      : m_nCount(1), m_pObj(ptr.release()) {}
+  void reset(std::unique_ptr<T> ptr) {  // CAUTION: tosses prior ref counts.
     m_nCount = 1;
-    m_pObj = ptr;
+    m_pObj = ptr.release();
   }
   void clear() {  // Now you're all weak ptrs ...
     // Guard against accidental re-entry.
     T* pObj = m_pObj;
     m_pObj = nullptr;
     delete pObj;
   }
   T* get() const { return m_pObj; }
   T* AddRef() {
     ASSERT(m_pObj);
     ++m_nCount;
     return m_pObj;
   }
   void RemoveRef() {
     if (m_nCount)
       --m_nCount;
   }
   size_t use_count() const { return m_nCount; }
 
  protected:
   size_t m_nCount;
   T* m_pObj;
 };
 using CPDF_CountedColorSpace = CPDF_CountedObject<CPDF_ColorSpace>;
 using CPDF_CountedPattern = CPDF_CountedObject<CPDF_Pattern>;
 
 #endif  // CORE_FPDFAPI_PAGE_CPDF_COUNTEDOBJECT_H_