[MD settings] CSS var --checkbox-spacing to --settings-control-spacing

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

 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys/iron-a11y-keys.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-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="internet_shared_css.html">
@@ skipping 28 matching lines @@
       /* Siminfo is embedded; remove the padding. */
       .settings-box {
         padding: 0;
       }
 
       .settings-box:first-of-type {
         border-top: none;
       }
 
       paper-toggle-button {
-        -webkit-margin-start: var(--checkbox-spacing);
+        -webkit-margin-start: var(--settings-control-spacing);
       }
     </style>
 
     <!-- SIM missing UI -->
     <div class="settings-box two-line"
         hidden$="[[networkProperties.Cellular.SIMPresent]]">
       <div class="start layout horizontal center">
         <iron-icon icon="settings:sim-card-alert"></iron-icon>
         <div class="error">$i18n{networkSimCardMissing}</div>
       </div>
@@ skipping 122 matching lines @@
       </div>
       <div class="button-container">
         <paper-button on-tap="sendUnlockPuk_">
           $i18n{networkSimUnlock}
         </paper-button>
       </div>
     </dialog>
   </template>
   <script src="network_siminfo.js"></script>
 </dom-module>