Standardize usage of virtual/override/final in net/

net/disk_cache/entry_unittest.cc

Index: net/disk_cache/entry_unittest.cc
diff --git a/net/disk_cache/entry_unittest.cc b/net/disk_cache/entry_unittest.cc
index a3a774793ebc7f3122adfecd4ae6f7a04f814037..60811370a207e46487599644791c0da39a7ac870 100644
--- a/net/disk_cache/entry_unittest.cc
+++ b/net/disk_cache/entry_unittest.cc
@@ -2063,7 +2063,7 @@ class SparseTestCompletionCallback: public net::TestCompletionCallback {
   }
 
  private:
-  virtual void SetResult(int result) override {
+  void SetResult(int result) override {
     cache_.reset();
     TestCompletionCallback::SetResult(result);
   }