VM: Make indirect subclasses of StackResource have virtual destructor

runtime/vm/timeline.h

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_TIMELINE_H_
 #define RUNTIME_VM_TIMELINE_H_
 
 #include "include/dart_tools_api.h"
 
 #include "vm/allocation.h"
@@ skipping 443 matching lines @@
 
 
 class TimelineDurationScope : public TimelineEventScope {
  public:
   TimelineDurationScope(TimelineStream* stream, const char* label);
 
   TimelineDurationScope(Thread* thread,
                         TimelineStream* stream,
                         const char* label);
 
-  ~TimelineDurationScope();
+  virtual ~TimelineDurationScope();
 
  private:
   int64_t timestamp_;
   int64_t thread_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(TimelineDurationScope);
 };
 
 
 class TimelineBeginEndScope : public TimelineEventScope {
  public:
   TimelineBeginEndScope(TimelineStream* stream, const char* label);
 
   TimelineBeginEndScope(Thread* thread,
                         TimelineStream* stream,
                         const char* label);
 
-  ~TimelineBeginEndScope();
+  virtual ~TimelineBeginEndScope();
 
  private:
   void EmitBegin();
   void EmitEnd();
 
   DISALLOW_COPY_AND_ASSIGN(TimelineBeginEndScope);
 };
 
 
 // A block of |TimelineEvent|s. Not thread safe.
@@ skipping 327 matching lines @@
 
  private:
   TimelineEventBlock* current_;
   TimelineEventRecorder* recorder_;
 };
 
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_TIMELINE_H_