Add Media Router cast-mode-picker.

chrome/browser/resources/media_router/elements/cast_mode_picker/cast_mode_picker.js

Index: chrome/browser/resources/media_router/elements/cast_mode_picker/cast_mode_picker.js
diff --git a/chrome/browser/resources/media_router/elements/cast_mode_picker/cast_mode_picker.js b/chrome/browser/resources/media_router/elements/cast_mode_picker/cast_mode_picker.js
new file mode 100644
index 0000000000000000000000000000000000000000..1b0fc14276abf7501cd778f9f7ec0afc1224bd41
--- /dev/null
+++ b/chrome/browser/resources/media_router/elements/cast_mode_picker/cast_mode_picker.js
@@ -0,0 +1,50 @@
+// Copyright 2015 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.
+
+Polymer('cast-mode-picker', {
+  publish: {
+    /**
+     * The list of CastModes to show.
+     *
+     * @attribute castModeList
+     * @type {!Array<!media_router.CastMode>}
+     * @default []
+     */
+    castModeList: [],
+
+    /**
+     * Maps each cast mode ID to the type of cast mode.
+     *
+     * @attribute castModeMap
+     * @type {!Object<number, !media_router.CastMode>}
+     * @default {}
+    */
+    castModeMap: {}
+  },
+
+  created: function() {
+    this.castModeList = [];
+    this.castModeMap = {};
+
+    /**
+     * -1 means users did not select mode explicitly.
+     * @type {number}
+     */
+    this.selectedCastMode = -1;
+  },
+
+  castModeListChanged: function(oldValue, newValue) {
+    this.$.selectbox.size = Math.max(newValue.length, 1);
+    this.castModeMap = {};
+    this.castModeList.forEach(function(e) {
+      this.castModeMap[e.castMode] = e;
+    }, this);
+  },
+
+  onCastModeSelected: function(event, detail, sender) {
+    this.fire('cast-mode-click', {
+      headerText: this.castModeMap[sender.value].title
+    });
+  }
+});