[CrOS Tether] Add a connection dialog to md-settings.

chrome/browser/resources/settings/internet_page/tether_connection_dialog.js

+// Copyright 2017 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.
+
+/**
+ * @typedef {{
+ *   tetherNostDeviceName: string,
+ *   batteryPercentage: number,
+ *   connectionStrength: number,
+ *   isTetherHostCurrentlyOnWifi: boolean
+ * }}
+ */
+var TetherConnectionData;
+
+Polymer({
+  is: 'tether-connection-dialog',
+
+  behaviors: [I18nBehavior],
+
+  properties: {
+    /**
+     * The data used to display the tether connection dialog.
+     * @private {!TetherConnectionData|undefined}
+     */
+    tetherData_: {
+      type: Object,
+      // TODO(khorimoto): Remove this and use real data when available.
+      value: {
+        tetherNostDeviceName: 'Pixel XL',
+        batteryPercentage: 100,
+        connectionStrength: 4,
+        isTetherHostCurrentlyOnWifi: false
+      },
+    },
+  },
+
+  open: function() {
+    var dialog = this.getDialog_();
+    if (!dialog.open)
+      this.getDialog_().showModal();
+  },
+
+  close: function() {
+    var dialog = this.getDialog_();
+    if (dialog.open)
+      dialog.close();
+  },
+
+  /**
+   * @return {!CrDialogElement}
+   * @private
+   */
+  getDialog_: function() {
+    return /** @type {!CrDialogElement} */ (this.$.dialog);
+  },
+
+  /** @private */
+  onNotNowTap_: function() {
+    this.getDialog_().cancel();
+  },
+
+  /**
+   * @param {!TetherConnectionData|undefined} tetherData
+   * @return {string}
+   * @private
+   */
+  getReceptionIcon_: function(tetherData) {
+    var connectionStrength;
+
+    if (!tetherData || !tetherData.connectionStrength) {
+      connectionStrength = 0;
+    } else {
+      // Ensure that 0 <= connectionStrength <= 4, since these values are the
+      // limits of the cellular strength icons.
+      connectionStrength =
+          Math.min(Math.max(tetherData.connectionStrength, 0), 4);
+    }
+
+    return 'settings:signal-cellular-' + connectionStrength + '-bar';
+  }
+});