Update {virtual,override} to follow C++11 style in base.

base/test/gtest_xml_util.h

Index: base/test/gtest_xml_util.h
diff --git a/base/test/gtest_xml_util.h b/base/test/gtest_xml_util.h
index f832cdea8d55807f4d8ab1dac3ca1d7b580e34cb..9ff2406728a500d7b46610a99966dbbacac43401 100644
--- a/base/test/gtest_xml_util.h
+++ b/base/test/gtest_xml_util.h
@@ -21,17 +21,17 @@ struct TestResult;
 class XmlUnitTestResultPrinter : public testing::EmptyTestEventListener {
  public:
   XmlUnitTestResultPrinter();
-  virtual ~XmlUnitTestResultPrinter();
+  ~XmlUnitTestResultPrinter() override;
 
   // Must be called before adding as a listener. Returns true on success.
   bool Initialize(const FilePath& output_file_path) WARN_UNUSED_RESULT;
 
  private:
   // testing::EmptyTestEventListener:
-  virtual void OnTestCaseStart(const testing::TestCase& test_case) override;
-  virtual void OnTestStart(const testing::TestInfo& test_info) override;
-  virtual void OnTestEnd(const testing::TestInfo& test_info) override;
-  virtual void OnTestCaseEnd(const testing::TestCase& test_case) override;
+  void OnTestCaseStart(const testing::TestCase& test_case) override;
+  void OnTestStart(const testing::TestInfo& test_info) override;
+  void OnTestEnd(const testing::TestInfo& test_info) override;
+  void OnTestCaseEnd(const testing::TestCase& test_case) override;
 
   FILE* output_file_;