Update {virtual,override,final} to follow C++11 style in chromeos.

chromeos/process_proxy/process_output_watcher_unittest.cc

Index: chromeos/process_proxy/process_output_watcher_unittest.cc
diff --git a/chromeos/process_proxy/process_output_watcher_unittest.cc b/chromeos/process_proxy/process_output_watcher_unittest.cc
index f08a852867aaf19bb813b13de0e1952a51c097f1..5732467943b32f0e0508fd8bbcfb4cada61f455d 100644
--- a/chromeos/process_proxy/process_output_watcher_unittest.cc
+++ b/chromeos/process_proxy/process_output_watcher_unittest.cc
@@ -88,9 +88,9 @@ class ProcessOutputWatcherTest : public testing::Test {
                                failed_(false) {
   }
 
-  virtual ~ProcessOutputWatcherTest() {}
+  ~ProcessOutputWatcherTest() override {}
 
-  virtual void TearDown() override {
+  void TearDown() override {
     if (output_watch_thread_started_)
       output_watch_thread_->Stop();
   }