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

jingle/notifier/base/xmpp_connection_unittest.cc

Index: jingle/notifier/base/xmpp_connection_unittest.cc
diff --git a/jingle/notifier/base/xmpp_connection_unittest.cc b/jingle/notifier/base/xmpp_connection_unittest.cc
index 2e620920d9ae473d4d7970c772944678f066413c..147edac22ac2c520e6b2048e08454b28bf09a56d 100644
--- a/jingle/notifier/base/xmpp_connection_unittest.cc
+++ b/jingle/notifier/base/xmpp_connection_unittest.cc
@@ -83,9 +83,9 @@ class XmppConnectionTest : public testing::Test {
         message_loop_->message_loop_proxy());
   }
 
-  virtual ~XmppConnectionTest() {}
+  ~XmppConnectionTest() override {}
 
-  virtual void TearDown() {
+  void TearDown() override {
     // Clear out any messages posted by XmppConnection's destructor.
     message_loop_->RunUntilIdle();
   }