Remove util.makeFilesystemUrl in Files app.

BUG=325029
TEST=none

Review URL: https://codereview.chromium.org/559843003

Cr-Commit-Position: refs/heads/master@{#294115}

ui/file_manager/file_manager/common/js/util.js

@@ -457,17 +457,6 @@ util.applyTransform = function(element, transform) {
       '';
 };
 
-/**
- * Makes filesystem: URL from the path.
- * @param {string} path File or directory path.
- * @return {string} URL.
- */
-util.makeFilesystemUrl = function(path) {
-  path = path.split('/').map(encodeURIComponent).join('/');
-  var prefix = 'external';
-  return 'filesystem:' + chrome.runtime.getURL(prefix + path);
-};
-
 /**
  * Extracts path from filesystem: URL.
  * @param {string} url Filesystem URL.