snapshot: Make destructors of interface classes public and virtual

snapshot/system_snapshot.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 11 matching lines @@
 
 #include "snapshot/cpu_architecture.h"
 
 namespace crashpad {
 
 //! \brief An abstract interface to a snapshot representing the state of a
 //!     system, comprising an operating system, CPU architecture, and various
 //!     other characteristics.
 class SystemSnapshot {
  public:
+  virtual ~SystemSnapshot() {}
+
   //! \brief A system’s operating system family.
   enum OperatingSystem {
     //! \brief The snapshot system’s operating system is unknown.
     kOperatingSystemUnknown = 0,
 
     //! \brief Mac OS X.
     kOperatingSystemMacOSX,
   };
 
   //! \brief A system’s daylight saving time status.
@@ skipping 206 matching lines @@
   //!     time.
   //! \param[out] standard_name The name of the time zone while standard time is
   //!     being observed.
   //! \param[out] daylight_name The name of the time zone while daylight saving
   //!     time is being observed.
   virtual void TimeZone(DaylightSavingTimeStatus* observes_daylight,
                         int* standard_offset_seconds,
                         int* daylight_offset_seconds,
                         std::string* standard_name,
                         std::string* daylight_name) const = 0;
-
- protected:
-  ~SystemSnapshot() {}
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_SNAPSHOT_SYSTEM_SNAPSHOT_H_