explicit operator bool for CFX_RetainPtr and CFX_CountRef

core/fxcrt/include/cfx_count_ref.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_FXCRT_INCLUDE_CFX_COUNT_REF_H_
 #define CORE_FXCRT_INCLUDE_CFX_COUNT_REF_H_
 
 #include "core/fxcrt/include/cfx_retain_ptr.h"
@@ skipping 29 matching lines @@
       return Emplace(params...);
     if (!m_pObject->HasOneRef())
       m_pObject.Reset(new CountedObj(*m_pObject));
     return m_pObject.Get();
   }
 
   bool operator==(const CFX_CountRef& that) const {
     return m_pObject == that.m_pObject;
   }
   bool operator!=(const CFX_CountRef& that) const { return !(*this == that); }
-  operator bool() const { return m_pObject; }
+  explicit operator bool() const { return !!m_pObject; }
 
  private:
   class CountedObj : public ObjClass {
    public:
     template <typename... Args>
     CountedObj(Args... params) : ObjClass(params...), m_RefCount(0) {}
 
     CountedObj(const CountedObj& src) : ObjClass(src), m_RefCount(0) {}
 
     bool HasOneRef() const { return m_RefCount == 1; }
     void Retain() { m_RefCount++; }
     void Release() {
       if (--m_RefCount <= 0)
         delete this;
     }
 
    private:
     intptr_t m_RefCount;
   };
 
   CFX_RetainPtr<CountedObj> m_pObject;
 };
 
 #endif  // CORE_FXCRT_INCLUDE_CFX_COUNT_REF_H_