MD Settings: fix some dynamically bound aria-labels

chrome/browser/resources/settings/site_settings/site_list.html

 <link rel="import" href="chrome://resources/cr_elements/cr_action_menu/cr_action_menu.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.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="../i18n_setup.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../route.html">
 <link rel="import" href="../settings_shared_css.html">
@@ skipping 72 matching lines @@
               <iron-icon icon="[[computeIconControlledBy_(item)]]"></iron-icon>
             </template>
 
             <paper-icon-button id="dots" icon="cr:more-vert"
                 hidden="[[isActionMenuHidden_(item.source)]]"
                 on-tap="onShowActionMenuTap_" title="$i18n{moreActions}">
             </paper-icon-button>
             <template is="dom-if" if="[[enableSiteSettings_]]">
               <div on-tap="onOriginTap_" actionable>
                 <button class="subpage-arrow" is="paper-icon-button-light"
-                    aria-label="[[item.displayName]]"
+                    aria-label$="[[item.displayName]]"
                     aria-describedby="siteDescription"></button>
               </div>
             </template>
           </div>
         </template>
       </div>
     </div>
     <template is="dom-if" if="[[showEditExceptionDialog_]]" restamp>
       <settings-edit-exception-dialog model="[[actionMenuSite_]]"
           on-close="onEditExceptionDialogClosed_">
       </settings-edit-exception-dialog>
     </template>
   </template>
   <script src="site_list.js"></script>
 </dom-module>