[Polymer] Roll polymer to latest version

third_party/polymer/v1_0/components-chromium/paper-menu-button/paper-menu-button.html

Index: third_party/polymer/v1_0/components-chromium/paper-menu-button/paper-menu-button.html
diff --git a/third_party/polymer/v1_0/components-chromium/paper-menu-button/paper-menu-button.html b/third_party/polymer/v1_0/components-chromium/paper-menu-button/paper-menu-button.html
index 8152ab66d56fc6dd444f0b891b014d2fb5177da1..6eb8aca2d76317c94e6c4c425b33efcdb6c2e29e 100644
--- a/third_party/polymer/v1_0/components-chromium/paper-menu-button/paper-menu-button.html
+++ b/third_party/polymer/v1_0/components-chromium/paper-menu-button/paper-menu-button.html
@@ -17,6 +17,8 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 <link rel="import" href="paper-menu-button-animations.html">
 
 <!--
+Material design: [Dropdown buttons](https://www.google.com/design/spec/components/buttons.html#buttons-dropdown-buttons)
+
 `paper-menu-button` allows one to compose a designated "trigger" element with
 another element that represents "content", to create a dropdown menu that
 displays the "content" when the "trigger" is clicked.
@@ -50,7 +52,7 @@ Custom property | Description | Default
 `--paper-menu-button` | Mixin applied to the paper-menu-button | `{}`
 `--paper-menu-button-disabled` | Mixin applied to the paper-menu-button when disabled | `{}`
 `--paper-menu-button-dropdown` | Mixin applied to the paper-menu-button dropdown | `{}`
-
+`--paper-menu-button-content` | Mixin applied to the paper-menu-button content | `{}`
 
 @hero hero.svg
 @demo demo/index.html
@@ -86,11 +88,14 @@ Custom property | Description | Default
       margin-top: 20px;
     }
 
-    paper-material {
+    iron-dropdown {
+      @apply(--paper-menu-button-dropdown);
+    }
+
+    .dropdown-content {
       border-radius: 2px;
       background-color: var(--paper-menu-button-dropdown-background, --primary-background-color);
-
-      @apply(--paper-menu-button-dropdown);
+      @apply(--paper-menu-button-content);
     }
   </style>
   <template>