The Google C++ style guide states: Explicitly annotate overrides of virtual functions or virtual destructors with an override or (less frequently) final specifier. Older (pre-C++11) code will use the virtual keyword as an inferior alternative annotation. For clarity, use exactly one of override, final, or virtual when declaring an override. To better conform to these guidelines, the following constructs have been rewritten: - if a base class has a virtual destructor, then: virtual ~Foo(); -> ~Foo() override; - virtual void Foo() override; -> void Foo() override; - virtual void Foo() override final; -> void Foo() final; This patch was automatically generated. The clang plugin can generate fixit hints, which are suggested edits when it is 100% sure it knows how to fix a problem. The hints from the clang plugin were applied to the source tree using the tool in https://codereview.chromium.org/598073004. BUG=417463 R=flackr@chromium.org Review URL: https://codereview.chromium.org/645513008 Cr-Commit-Position: refs/heads/master@{#301541}