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

media/cdm/ppapi/cdm_file_io_impl.h

Index: media/cdm/ppapi/cdm_file_io_impl.h
diff --git a/media/cdm/ppapi/cdm_file_io_impl.h b/media/cdm/ppapi/cdm_file_io_impl.h
index d885f1cad3500d774b39d4e640423fde97b9464c..8e7a88b1a20a68c27721eaafc50f1043089ca3c6 100644
--- a/media/cdm/ppapi/cdm_file_io_impl.h
+++ b/media/cdm/ppapi/cdm_file_io_impl.h
@@ -54,10 +54,10 @@ class CdmFileIOImpl : public cdm::FileIO {
                 const pp::CompletionCallback& first_file_read_cb);
 
   // cdm::FileIO implementation.
-  virtual void Open(const char* file_name, uint32_t file_name_size) override;
-  virtual void Read() override;
-  virtual void Write(const uint8_t* data, uint32_t data_size) override;
-  virtual void Close() override;
+  void Open(const char* file_name, uint32_t file_name_size) override;
+  void Read() override;
+  void Write(const uint8_t* data, uint32_t data_size) override;
+  void Close() override;
 
  private:
   // TODO(xhwang): Introduce more detailed states for UMA logging if needed.