[third_party] add polymer 1.2.3

polymer_1.2.3/bower_components/paper-menu/paper-menu-shared-styles.html

+<!--
+@license
+Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+
+<dom-module id="paper-menu-shared-styles">
+  <template>
+    <style>
+      /* need a wrapper element to make this higher specificity than the :host rule in paper-item */
+      .selectable-content > ::content > .iron-selected {
+        font-weight: bold;
+
+        @apply(--paper-menu-selected-item);
+      }
+
+      .selectable-content > ::content > [disabled] {
+        color: var(--paper-menu-disabled-color, --disabled-text-color);
+      }
+
+      .selectable-content > ::content > *:focus {
+        position: relative;
+        outline: 0;
+
+        @apply(--paper-menu-focused-item);
+      }
+
+      .selectable-content > ::content > *:focus:after {
+        @apply(--layout-fit);
+        background: currentColor;
+        opacity: var(--dark-divider-opacity);
+        content: '';
+
+        @apply(--paper-menu-focused-item-after);
+      }
+
+      .selectable-content > ::content > *[colored]:focus:after {
+        opacity: 0.26;
+      }
+    </style>
+  </template>
+</dom-module>