Prototype implementation of MediaImportHandler.

chrome/test/data/file_manager/unit_tests/mocks/mock_media_scanner.js

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * A fake media scanner for testing.
+ * @constructor
+ * @struct
+ */
+function MockMediaScanner() {
+  /** @private {!Array<!FileEntry>} */
+  this.results_ = [];
+}
+
+/**
+ * Returns scan "results".
+ * @return {!Promise<!Array<!FileEntry>>}
+ */
+MockMediaScanner.prototype.scan = function(entries) {
+  return Promise.resolve(this.results_);
+};
+
+/**
+ * Sets the entries that the scanner will return.
+ * @param {!Array<!FileEntry>} entries
+ */
+MockMediaScanner.prototype.setScanResults = function(entries) {
+  this.results_ = entries;
+};