Add virtual and OVERRIDE to base/ implementation files

base/tracked_objects_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.
 
 // Test of classes in the tracked_objects.h classes.
 
 #include "base/tracked_objects.h"
 
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace tracked_objects {
 
 class TrackedObjectsTest : public testing::Test {
  protected:
   TrackedObjectsTest() {
     // On entry, leak any database structures in case they are still in use by
     // prior threads.
     ThreadData::ShutdownSingleThreadedCleanup(true);
   }
 
-  ~TrackedObjectsTest() {
+  virtual ~TrackedObjectsTest() {
     // We should not need to leak any structures we create, since we are
     // single threaded, and carefully accounting for items.
     ThreadData::ShutdownSingleThreadedCleanup(false);
   }
 
   // Provide access, since this class is a friend of ThreadData.
   void ShutdownSingleThreadedCleanup(bool leak) {
     ThreadData::ShutdownSingleThreadedCleanup(leak);
   }
 };
@@ skipping 778 matching lines @@
             "\"line_number\":999"
           "}"
         "}"
       "]"
     "}";
   EXPECT_EQ(one_line_result, json);
 }
 
 
 }  // namespace tracked_objects