Standardize usage of virtual/override/final in extensions/

extensions/browser/api/power/power_api_unittest.cc

Index: extensions/browser/api/power/power_api_unittest.cc
diff --git a/extensions/browser/api/power/power_api_unittest.cc b/extensions/browser/api/power/power_api_unittest.cc
index ce6a2518327b0d93da956313d1e4b5abdd46fbd7..af44d30c523fd933b3cba51a45577969047c83a5 100644
--- a/extensions/browser/api/power/power_api_unittest.cc
+++ b/extensions/browser/api/power/power_api_unittest.cc
@@ -47,9 +47,7 @@ class PowerSaveBlockerStub : public content::PowerSaveBlocker {
       : unblock_callback_(unblock_callback) {
   }
 
-  virtual ~PowerSaveBlockerStub() {
-    unblock_callback_.Run();
-  }
+  ~PowerSaveBlockerStub() override { unblock_callback_.Run(); }
 
  private:
   base::Closure unblock_callback_;