Standardize usage of virtual/override/final specifiers in tools/.

tools/gn/loader_unittest.cc

 // Copyright (c) 2013 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 <map>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/memory/linked_ptr.h"
@@ skipping 99 matching lines @@
   pending_.clear();
 }
 
 // LoaderTest ------------------------------------------------------------------
 
 class LoaderTest : public testing::Test {
  public:
   LoaderTest() {
     build_settings_.SetBuildDir(SourceDir("//out/Debug/"));
   }
-  virtual ~LoaderTest() {
-  }
 
  protected:
   Scheduler scheduler_;
   BuildSettings build_settings_;
   MockInputFileManager mock_ifm_;
 };
 
 }  // namespace
 
 // -----------------------------------------------------------------------------
@@ skipping 49 matching lines @@
   loader->Load(third_file, LocationRange(), second_tc);
   EXPECT_TRUE(mock_ifm_.HasOnePending(build_config));
 
   // Running the build config file should make our third file pending.
   mock_ifm_.IssueAllPending();
   scheduler_.main_loop()->RunUntilIdle();
   EXPECT_TRUE(mock_ifm_.HasTwoPending(second_file, third_file));
 
   EXPECT_FALSE(scheduler_.is_failed());
 }