[MD Extensions] Move search field out of downloads, use it in extensions

chrome/browser/resources/md_downloads/toolbar.html

 <link rel="import" href="chrome://resources/polymer/v1_0/polymer/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-input/iron-input.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
-<link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input-container.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-item/paper-item.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu/paper-menu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu-button/paper-menu-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/cr.html">
+<link rel="import" href="chrome://resources/html/cr/ui/search_field.html">
 
 <dom-module id="downloads-toolbar">
   <template>
     <div id="title">
       <h1 i18n-content="title"></h1>
     </div>
     <div id="actions">
       <paper-button class="clear-all" i18n-content="clearAll"
           on-click="onClearAllClick_"></paper-button>
       <paper-button i18n-content="openDownloadsFolder"
           on-click="onOpenDownloadsFolderClick_"></paper-button>
     </div>
     <div id="search">
-      <paper-icon-button icon="search" id="search-button"
-          on-click="toggleShowingSearch_"></paper-icon-button>
-      <paper-input-container id="search-term" on-search="onSearchTermSearch_"
-          on-keydown="onSearchTermKeydown_" hidden$="[[!showingSearch_]]"
-          no-label-float>
-        <input is="iron-input" id="search-input" type="search"
-            i18n-values="placeholder:search" incremental>
-        <paper-icon-button icon="cancel" id="clear-search"
-            on-click="toggleShowingSearch_"
-            hidden$="[[!showingSearch_]]"></paper-icon-button>
-      </paper-input-container>
+      <search-field id="search-input"></search-field>
       <paper-menu-button id="more" horizontal-align="right">
         <paper-icon-button icon="more-vert"
             class="dropdown-trigger"></paper-icon-button>
         <paper-menu class="dropdown-content">
           <paper-item class="clear-all" i18n-content="clearAll"
               on-click="onClearAllClick_"></paper-item>
           <paper-item i18n-content="openDownloadsFolder"
               on-click="onOpenDownloadsFolderClick_"></paper-item>
         </paper-menu>
       </paper-menu-button>
     </div>
   </template>
   <link rel="import" type="css" href="chrome://downloads/shared_style.css">
   <link rel="import" type="css" href="chrome://downloads/toolbar.css">
   <script src="chrome://downloads/toolbar.js"></script>
 </dom-module>