MD Downloads: compute content classes via data binding

chrome/browser/resources/md_downloads/item.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('downloads', function() {
   var Item = Polymer({
     is: 'downloads-item',
 
     /**
      * @param {!downloads.ThrottledIconLoader} iconLoader
@@ skipping 129 matching lines @@
           data.total == this.data_.total &&
           data.url == this.data_.url) {
         // TODO(dbeam): remove this once data binding is fully in place.
         return;
       }
 
       for (var key in data) {
         this.set('data_.' + key, data[key]);
       }
 
-      // TODO(dbeam): Move to a computeClass_() method + data binding.
-      this.$.content.classList.toggle('is-active', this.isActive_);
-      this.$.content.classList.toggle('dangerous', this.isDangerous_);
-      this.$.content.classList.toggle('show-progress', this.showProgress_);
-
       var desc = this.getDangerText_(data) || this.getStatusText_(data);
 
       // Status goes in the "tag" (next to the file name) if there's no file.
       this.ensureTextIs_(this.$.description, this.isActive_ ? desc : '');
       this.ensureTextIs_(this.$.tag, this.isActive_ ? '' : desc);
 
       if (!this.isDangerous_) {
         /** @const */ var controlledByExtension = data.by_ext_id &&
                                                   data.by_ext_name;
         this.$['controlled-by'].hidden = !controlledByExtension;
         if (controlledByExtension) {
           var link = this.$['controlled-by'].querySelector('a');
           link.href = 'chrome://extensions#' + data.by_ext_id;
           link.textContent = data.by_ext_name;
         }
 
         var icon = 'chrome://fileicon/' + encodeURIComponent(data.file_path);
         this.iconLoader_.loadScaledIcon(this.$['file-icon'], icon);
       }
     },
 
     /** @private */
+    computeClass_: function() {
+      var classes = [];
+
+      if (this.isActive_)
+        classes.push('is-active');
+
+      if (this.isDangerous_)
+        classes.push('dangerous');
+
+      if (this.showProgress_)
+        classes.push('show-progress');
+
+      return classes.join(' ');
+    },
+
+    /** @private */
     computeCompletelyOnDisk_: function() {
       return this.data_.state == downloads.States.COMPLETE &&
              !this.data_.file_externally_removed;
     },
 
     /** @private */
     computeDate_: function() {
       assert(!this.hideDate);
       return assert(this.data_.since_string || this.data_.date_string);
     },
@@ skipping 182 matching lines @@
     },
 
     /** @private */
     onShowClick_: function() {
       this.actionService_.show(this.data_.id);
     },
   });
 
   return {Item: Item};
 });