Remove the Dromaeo and TodoMVC samples.

samples/third_party/todomvc_performance/web/elements/td_item.html

-<link rel="import" href="td_input.html">
-<polymer-element name="td-item" extends="li" on-blur="{{commitAction}}">
-  <template>
-    <link rel="stylesheet" href="td_item.css">
-    <div class="view {{ {'completed': item.completed, 'editing': editing} }}"
-        hidden?="{{editing}}" on-dblclick="{{editAction}}">
-      <input type="checkbox" class="toggle" checked="{{item.completed}}"
-          on-click="{{itemChangeAction}}">
-      <label>{{item.title}}</label>
-      <button class="destroy" on-click="{{destroyAction}}"></button>
-    </div>
-    <input is="td-input" id="edit" class="edit" value="{{item.title}}"
-        hidden?="{{!editing}}" on-td-input-commit="{{commitAction}}"
-        on-td-input-cancel="{{cancelAction}}">
-  </template>
-  <script type="application/dart" src="td_item.dart"></script>
-</polymer-element>