GTTF: Add missing virtual destructors.

base/debug/trace_event_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 #ifndef BASE_DEBUG_TRACE_EVENT_IMPL_H_
 #define BASE_DEBUG_TRACE_EVENT_IMPL_H_
 
 #include "build/build_config.h"
 
@@ skipping 199 matching lines @@
 
 #if defined(OS_ANDROID)
   static void InitATrace();
 #endif
 
   // Enabled state listeners give a callback when tracing is enabled or
   // disabled. This can be used to tie into other library's tracing systems
   // on-demand.
   class EnabledStateChangedObserver {
    public:
+    virtual ~EnabledStateChangedObserver() { }
+
     // Called just before the tracing system becomes
     // enabled. TraceLog::IsEnabled will return false at this point and trace
     // macros and methods called within the observer will deadlock.
     virtual void OnTraceLogWillEnable() { }
 
     // Called just before the tracing system disables. TraceLog::IsEnabled is
     // still false at this point TRACE macros will still be capturing
     // data. However, trace macros and methods called within the observer will
     // deadlock.
     virtual void OnTraceLogWillDisable() { }
@@ skipping 157 matching lines @@
   const unsigned char* watch_category_;
   std::string watch_event_name_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_TRACE_EVENT_IMPL_H_