MD Settings: Cleanup, remove obsolete dependencies.

chrome/browser/resources/settings/internet_page/network_summary_item.html

 <link rel="import" href="chrome://resources/cr_elements/cr_expand_button/cr_expand_button.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_network_list.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_network_list_item.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-collapse/iron-collapse.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-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-spinner/paper-spinner.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="/settings_shared_css.html">
 <link rel="import" href="network_siminfo.html">
 
 <dom-module name="network-summary-item">
   <template>
     <style include="settings-shared">
       paper-spinner {
         height: 20px;
         margin: 0 var(--settings-box-row-padding);
         width: 20px;
       }
 
       network-siminfo {
         padding: 0 var(--settings-box-row-padding);
       }
-      
+
       .button-row {
         align-items: center;
         display: flex;
         min-height: var(--settings-row-min-height);
       }
 
       #buttons {
         align-items: center;
       }
 
@@ skipping 68 matching lines @@
             <div class="button-row" actionable on-tap="onKnownNetworksTap_">
               <a is="action-link">$i18n{knownNetworksButton}</a>
             </div>
           </template>
         </div>
       </iron-collapse>
     </template>
   </template>
   <script src="network_summary_item.js"></script>
 </dom-module>