MD Downloads: compute description and tag via data binding

chrome/browser/resources/md_downloads/item.html

 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="chrome://resources/html/load_time_data.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/polymer/polymer.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-material/paper-material.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-progress/paper-progress.html">
 <link rel="import" href="chrome://downloads/action_service.html">
 <link rel="import" href="chrome://downloads/constants.html">
 <link rel="import" href="chrome://downloads/throttled_icon_loader.html">
@@ skipping 16 matching lines @@
 
       <div id="details">
         <div id="title-area"><!--
           Can't have any line breaks.
           --><a is="action-link" id="file-link" href$="[[data_.url]]"
               on-click="onFileLinkClick_"
               hidden$="[[!completelyOnDisk_]]">[[data_.file_name]]</a><!--
           Before #name.
           --><span id="name"
               hidden$="[[completelyOnDisk_]]">[[data_.file_name]]</span>
-          <span id="tag"></span>
+          <span id="tag">[[computeTag_(data_.state, data_.last_reason_text, data_.file_externally_removed)]]</span>
         </div>
 
         <a id="url" target="_blank" href$="[[data_.url]]">[[data_.url]]</a>
 
-        <div id="description"></div>
+        <div id="description">[[computeDescription_(data_.state, data_.danger_type, data_.file_name, data_.progress_status_text)]]</div>
 
         <template is="dom-if" if="[[showProgress_]]">
           <paper-progress id="progress"
               indeterminate$="[[isIndeterminate_(data_.percent)]]"
               value$="[[data_.percent]]"></paper-progress>
         </template>
 
         <div id="safe" class="controls" hidden$="[[isDangerous_]]">
           <template is="dom-if" if="[[completelyOnDisk_]]">
             <paper-button id="show" on-click="onShowClick_"
@@ skipping 50 matching lines @@
     </paper-material>
 
     <div id="end-cap"></div>
 
   </template>
   <link rel="import" type="css" href="chrome://resources/css/action_link.css">
   <link rel="import" type="css" href="chrome://downloads/shared_style.css">
   <link rel="import" type="css" href="chrome://downloads/item.css">
   <script src="chrome://downloads/item.js"></script>
 </dom-module>