Add some missing virtual destructors to base classes.

base/trace_event/trace_event_unittest.cc

 // 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.
 
 #include <math.h>
 #include <cstdlib>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
@@ skipping 1002 matching lines @@
 
   // Cleanup.
   TraceLog::GetInstance()->RemoveEnabledStateObserver(&observer);
 }
 
 // Tests the IsEnabled() state of TraceLog changes before callbacks.
 class AfterStateChangeEnabledStateObserver
     : public TraceLog::EnabledStateObserver {
  public:
   AfterStateChangeEnabledStateObserver() {}
-  virtual ~AfterStateChangeEnabledStateObserver() {}
+  ~AfterStateChangeEnabledStateObserver() override {}
 
   // TraceLog::EnabledStateObserver overrides:
   void OnTraceLogEnabled() override {
     EXPECT_TRUE(TraceLog::GetInstance()->IsEnabled());
   }
 
   void OnTraceLogDisabled() override {
     EXPECT_FALSE(TraceLog::GetInstance()->IsEnabled());
   }
 };
@@ skipping 10 matching lines @@
   EXPECT_FALSE(TraceLog::GetInstance()->IsEnabled());
 
   TraceLog::GetInstance()->RemoveEnabledStateObserver(&observer);
 }
 
 // Tests that a state observer can remove itself during a callback.
 class SelfRemovingEnabledStateObserver
     : public TraceLog::EnabledStateObserver {
  public:
   SelfRemovingEnabledStateObserver() {}
-  virtual ~SelfRemovingEnabledStateObserver() {}
+  ~SelfRemovingEnabledStateObserver() override {}
 
   // TraceLog::EnabledStateObserver overrides:
   void OnTraceLogEnabled() override {}
 
   void OnTraceLogDisabled() override {
     TraceLog::GetInstance()->RemoveEnabledStateObserver(this);
   }
 };
 
 TEST_F(TraceEventTestFixture, SelfRemovingObserver) {
@@ skipping 1893 matching lines @@
 }
 
 TEST_F(TraceEventTestFixture, SyntheticDelayConfigurationToString) {
   const char filter[] = "DELAY(test.Delay;16;oneshot)";
   TraceConfig config(filter, "");
   EXPECT_EQ(filter, config.ToCategoryFilterString());
 }
 
 }  // namespace trace_event
 }  // namespace base