Update {virtual,override,final} to follow C++11 style in chrome/browser/chromeos/drive.

chrome/browser/chromeos/drive/write_on_cache_file_unittest.cc

Index: chrome/browser/chromeos/drive/write_on_cache_file_unittest.cc
diff --git a/chrome/browser/chromeos/drive/write_on_cache_file_unittest.cc b/chrome/browser/chromeos/drive/write_on_cache_file_unittest.cc
index da1bb3714a801967c418f1aa450470a4945a86bc..cdbaff751e8bd5c7e1dc56fca66e6cc55fe8d661 100644
--- a/chrome/browser/chromeos/drive/write_on_cache_file_unittest.cc
+++ b/chrome/browser/chromeos/drive/write_on_cache_file_unittest.cc
@@ -30,10 +30,10 @@ class TestFileSystem : public DummyFileSystem {
   int num_closed() const { return num_closed_; }
 
   // Mimics OpenFile. It fails if the |file_path| points to a hosted document.
-  virtual void OpenFile(const base::FilePath& file_path,
-                        OpenMode open_mode,
-                        const std::string& mime_type,
-                        const OpenFileCallback& callback) override {
+  void OpenFile(const base::FilePath& file_path,
+                OpenMode open_mode,
+                const std::string& mime_type,
+                const OpenFileCallback& callback) override {
     EXPECT_EQ(OPEN_OR_CREATE_FILE, open_mode);
 
     // Emulate a case of opening a hosted document.