[MD Bookmarks] Make folder nodes extend their whole width.

chrome/browser/resources/md_bookmarks/folder_node.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/color.html">
 <link rel="import" href="chrome://bookmarks/actions.html">
 <link rel="import" href="chrome://bookmarks/icons.html">
 <link rel="import" href="chrome://bookmarks/shared_style.html">
 <link rel="import" href="chrome://bookmarks/store_client.html">
 
@@ skipping 14 matching lines @@
         -webkit-margin-start: 24px;
         color: var(--folder-inactive-color);
         font-weight: 500;
         overflow: hidden;
         text-overflow: ellipsis;
         white-space: nowrap;
       }
 
       #container {
         height: 40px;
-      }
-
-      #descendants {
-        -webkit-padding-start: 40.5px;
+        padding-left: calc(var(--node-depth, 0) * 30px);
       }
 
       #folder-label {
         color: var(--secondary-text-color);
         cursor: pointer;
         flex-grow: 1;
         overflow: hidden;
       }
 
       :host([is-selected-folder_]) .menu-label,
@@ skipping 24 matching lines @@
       <template is="dom-if" if="[[hasChildFolder_(item_.children)]]">
         <paper-icon-button icon="[[getArrowIcon_(isClosed_)]]"
             on-tap="toggleFolder_"></paper-icon-button>
       </template>
     </div>
     <div id="descendants" hidden$="[[isClosed_]]">
       <template is="dom-repeat"
           items="[[item_.children]]"
           as="child"
           filter="isFolder_">
-        <bookmarks-folder-node item-id="[[child]]">
+        <bookmarks-folder-node item-id="[[child]]"
+            depth="[[getChildDepth_(depth)]]">
         </bookmarks-folder-node>
       </template>
     </div>
   </template>
   <script src="chrome://bookmarks/folder_node.js"></script>
 </dom-module>