Standardize usage of virtual/override/final in net/

net/base/trace_net_log_observer.cc

Index: net/base/trace_net_log_observer.cc
diff --git a/net/base/trace_net_log_observer.cc b/net/base/trace_net_log_observer.cc
index 77945fbe8d98a0c0b05c8b26f14d99c4937c045a..15960c3b43d674290b228b5296847ed337ce1f4a 100644
--- a/net/base/trace_net_log_observer.cc
+++ b/net/base/trace_net_log_observer.cc
@@ -24,9 +24,9 @@ class TracedValue : public base::debug::ConvertableToTraceFormat {
   explicit TracedValue(scoped_ptr<base::Value> value) : value_(value.Pass()) {}
 
  private:
-  virtual ~TracedValue() {}
+  ~TracedValue() override {}
 
-  virtual void AppendAsTraceFormat(std::string* out) const override {
+  void AppendAsTraceFormat(std::string* out) const override {
     if (value_) {
       std::string tmp;
       base::JSONWriter::Write(value_.get(), &tmp);