Port storage manager to MD settings.

chrome/browser/resources/settings/device_page/drive_cache_dialog.js

+// Copyright 2016 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.
+
+/**
+ * @fileoverview
+ * 'settings-drive-cache-dialog' is the dialog to delete Google Drive temporary
+ * offline files.
+ */
+Polymer({
+  is: 'settings-drive-cache-dialog',
+
+  behaviors: [
+    I18nBehavior,
+  ],
+
+  open: function() {
+    this.$.dialog.showModal();
+  },
+
+  /** @private */
+  onCancelTap_: function() {
+    this.$.dialog.cancel();
+  },
+
+  /** @private */
+  onDeleteTap_: function() {
+    chrome.send('clearDriveCache');
+    this.$.dialog.close();
+  },
+});