Fix some chromium-style warnings in webrtc/system_wrappers/

BUG=163
R=henrike@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1906004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4464 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/system_wrappers/source/file_impl.h b/webrtc/system_wrappers/source/file_impl.h
index 5dbbcfb..8cc0979 100644
--- a/webrtc/system_wrappers/source/file_impl.h
+++ b/webrtc/system_wrappers/source/file_impl.h
@@ -26,23 +26,23 @@
   virtual ~FileWrapperImpl();
 
   virtual int FileName(char* file_name_utf8,
-                       size_t size) const;
+                       size_t size) const OVERRIDE;
 
-  virtual bool Open() const;
+  virtual bool Open() const OVERRIDE;
 
   virtual int OpenFile(const char* file_name_utf8,
                        bool read_only,
                        bool loop = false,
-                       bool text = false);
+                       bool text = false) OVERRIDE;
 
-  virtual int CloseFile();
-  virtual int SetMaxFileSize(size_t bytes);
-  virtual int Flush();
+  virtual int CloseFile() OVERRIDE;
+  virtual int SetMaxFileSize(size_t bytes) OVERRIDE;
+  virtual int Flush() OVERRIDE;
 
-  virtual int Read(void* buf, int length);
-  virtual bool Write(const void* buf, int length);
-  virtual int WriteText(const char* format, ...);
-  virtual int Rewind();
+  virtual int Read(void* buf, int length) OVERRIDE;
+  virtual bool Write(const void* buf, int length) OVERRIDE;
+  virtual int WriteText(const char* format, ...) OVERRIDE;
+  virtual int Rewind() OVERRIDE;
 
  private:
   int CloseFileImpl();