Add some missing virtual destructors to base classes.

base/trace_event/trace_event_memory.h

Index: base/trace_event/trace_event_memory.h
diff --git a/base/trace_event/trace_event_memory.h b/base/trace_event/trace_event_memory.h
index e2b3ae93060ade693c67a6717113f2ab9e42ebe9..5b63db0365c39300f2dbf1be0e8decaba8504220 100644
--- a/base/trace_event/trace_event_memory.h
+++ b/base/trace_event/trace_event_memory.h
@@ -43,7 +43,7 @@ class BASE_EXPORT TraceMemoryController
                         HeapProfilerStartFunction heap_profiler_start_function,
                         HeapProfilerStopFunction heap_profiler_stop_function,
                         GetHeapProfileFunction get_heap_profile_function);
-  virtual ~TraceMemoryController();
+  ~TraceMemoryController() override;
 
   // base::trace_event::TraceLog::EnabledStateChangedObserver overrides:
   void OnTraceLogEnabled() override;