Standardize usage of virtual/override/final in extensions/

extensions/renderer/static_v8_external_one_byte_string_resource.h

Index: extensions/renderer/static_v8_external_one_byte_string_resource.h
diff --git a/extensions/renderer/static_v8_external_one_byte_string_resource.h b/extensions/renderer/static_v8_external_one_byte_string_resource.h
index 97923b88fbe7cacf246307456cf6e393663825b2..5ffba3a2776739daddaf8257c0ac79e92734881c 100644
--- a/extensions/renderer/static_v8_external_one_byte_string_resource.h
+++ b/extensions/renderer/static_v8_external_one_byte_string_resource.h
@@ -19,10 +19,10 @@ class StaticV8ExternalOneByteStringResource
  public:
   explicit StaticV8ExternalOneByteStringResource(
       const base::StringPiece& buffer);
-  virtual ~StaticV8ExternalOneByteStringResource();
+  ~StaticV8ExternalOneByteStringResource() override;
 
-  virtual const char* data() const override;
-  virtual size_t length() const override;
+  const char* data() const override;
+  size_t length() const override;
 
  private:
   base::StringPiece buffer_;