Add RegisterMountPointProvider and TestMountPointProvider for testing

webkit/chromeos/fileapi/cros_mount_point_provider.cc

Index: webkit/chromeos/fileapi/cros_mount_point_provider.cc
diff --git a/webkit/chromeos/fileapi/cros_mount_point_provider.cc b/webkit/chromeos/fileapi/cros_mount_point_provider.cc
index 118ffa87f844920c17ff39ecb4c5b4fc4e6c1d9b..d7963996de1c659039856d2f3690957757ced1d5 100644
--- a/webkit/chromeos/fileapi/cros_mount_point_provider.cc
+++ b/webkit/chromeos/fileapi/cros_mount_point_provider.cc
@@ -131,6 +131,11 @@ bool CrosMountPointProvider::IsRestrictedFileName(const FilePath& path) const {
   return false;
 }
 
+fileapi::FileSystemQuotaUtil* CrosMountPointProvider::GetQuotaUtil() {
+  // No quota support.
+  return NULL;
+}
+
 bool CrosMountPointProvider::HasMountPoint(const FilePath& mount_point) {
   base::AutoLock locker(mount_point_map_lock_);
   MountPointMap::const_iterator iter = mount_point_map_.find(