Share MediaStorageUtil common code among platforms.

chrome/browser/system_monitor/media_storage_util.h

Index: chrome/browser/system_monitor/media_storage_util.h
diff --git a/chrome/browser/system_monitor/media_storage_util.h b/chrome/browser/system_monitor/media_storage_util.h
index ae0a49593e7b048bf74f53818028be89716af37e..df146eb4a7cab0ec4596b4e60101aaafa16bc76b 100644
--- a/chrome/browser/system_monitor/media_storage_util.h
+++ b/chrome/browser/system_monitor/media_storage_util.h
@@ -83,12 +83,6 @@ class MediaStorageUtil {
   // All methods are static, this class should not be instantiated.
   MediaStorageUtil();
 
-  // Per platform implementation.
-  static bool GetDeviceInfoFromPathImpl(const FilePath& path,
-                                        std::string* device_id,
-                                        string16* device_name,
-                                        FilePath* relative_path);
-
   DISALLOW_COPY_AND_ASSIGN(MediaStorageUtil);
 };