Standardize usage of virtual/override/final specifiers.

extensions/renderer/module_system_test.h

Index: extensions/renderer/module_system_test.h
diff --git a/extensions/renderer/module_system_test.h b/extensions/renderer/module_system_test.h
index 58501abfa0a4ddd56c3816699a3cb8e7a25b8f81..dd2686ba35902a40137543889f661d774b65f96f 100644
--- a/extensions/renderer/module_system_test.h
+++ b/extensions/renderer/module_system_test.h
@@ -79,10 +79,10 @@ class ModuleSystemTestEnvironment {
 class ModuleSystemTest : public testing::Test {
  public:
   ModuleSystemTest();
-  virtual ~ModuleSystemTest();
+  ~ModuleSystemTest() override;
 
-  virtual void SetUp() override;
-  virtual void TearDown() override;
+  void SetUp() override;
+  void TearDown() override;
 
  protected:
   ModuleSystemTestEnvironment* env() { return env_.get(); }