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

base/threading/worker_pool_posix_unittest.cc

Index: base/threading/worker_pool_posix_unittest.cc
diff --git a/base/threading/worker_pool_posix_unittest.cc b/base/threading/worker_pool_posix_unittest.cc
index b694155fdfd230cbed11d37add69a5e35a460d6c..354a99c538d74f831678f74d1065574d6518d331 100644
--- a/base/threading/worker_pool_posix_unittest.cc
+++ b/base/threading/worker_pool_posix_unittest.cc
@@ -97,11 +97,11 @@ class PosixDynamicThreadPoolTest : public testing::Test {
         num_waiting_to_start_cv_(&num_waiting_to_start_lock_),
         start_(true, false) {}
 
-  virtual void SetUp() override {
+  void SetUp() override {
     peer_.set_num_idle_threads_cv(new ConditionVariable(peer_.lock()));
   }
 
-  virtual void TearDown() override {
+  void TearDown() override {
     // Wake up the idle threads so they can terminate.
     if (pool_.get()) pool_->Terminate();
   }