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

chrome_elf/create_file/chrome_create_file_unittest.cc

Index: chrome_elf/create_file/chrome_create_file_unittest.cc
diff --git a/chrome_elf/create_file/chrome_create_file_unittest.cc b/chrome_elf/create_file/chrome_create_file_unittest.cc
index cd66d47068857d91ea65148260cb96e151587bc0..8b0331fe88d7095e52c90e0348275336800bb2d9 100644
--- a/chrome_elf/create_file/chrome_create_file_unittest.cc
+++ b/chrome_elf/create_file/chrome_create_file_unittest.cc
@@ -76,7 +76,7 @@ class ChromeCreateFileTest : public PlatformTest {
         path);
   }
 
-  virtual void SetUp() override {
+  void SetUp() override {
     original_thread_ = base::PlatformThread::CurrentId();
     InitCache();
     PlatformTest::SetUp();