[MD settings] using h2 for sub-headers consistently.

chrome/browser/resources/settings/passwords_and_forms_page/autofill_section.html

 <link rel="import" href="chrome://resources/cr_elements/cr_shared_menu/cr_shared_menu.html">
 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="/passwords_and_forms_page/address_edit_dialog.html">
 <link rel="import" href="/passwords_and_forms_page/credit_card_edit_dialog.html">
 <link rel="import" href="/passwords_and_forms_page/passwords_shared_css.html">
 <link rel="import" href="/settings_shared_css.html">
 
 <dom-module id="settings-autofill-section">
@@ skipping 21 matching lines @@
 
       .expiration-date {
         flex: 1;
       }
 
       .payments-label {
         -webkit-margin-start: 16px;
         color: var(--paper-grey-600);
       }
     </style>
-    <div class="heading">$i18n{addresses}</div>
+    <h2>$i18n{addresses}</h2>
     <div class="item-list">
       <div id="addressList" class="vertical-list list-section">
         <template is="dom-repeat" items="[[addresses]]">
           <div class="list-item two-line">
             <div class="start">
               <span id="addressSummary">[[address_(item)]]</span>
               <span class="payments-label" hidden$="[[item.metadata.isLocal]]">
                 $i18n{googlePayments}
               </span>
             </div>
@@ skipping 12 matching lines @@
       <button id="menuEditAddress" class="list-item menu-item"
           on-tap="onMenuEditAddressTap_">$i18n{editAddress}</button>
       <button id="menuRemoveAddress" class="list-item menu-item"
           on-tap="onMenuRemoveAddressTap_">$i18n{removeAddress}</button>
     </cr-shared-menu>
     <template is="dom-if" if="[[activeAddress]]" restamp>
       <settings-address-edit-dialog address="[[activeAddress]]"
           on-close="unstampAddressEditDialog_">
       </settings-address-edit-dialog>
     </template>
-    <div class="heading">$i18n{creditCards}</div>
+    <h2>$i18n{creditCards}</h2>

[hcarmona, 2016/08/24 23:41:21]

Looks like this add some extra space between the lists.

[dschuyler, 2016/08/25 02:00:53]

I was separating the CLs. I have more changes to go after this.

     <div class="item-list">
       <div class="list-item column-header">
         <div class="type-column">$i18n{creditCardType}</div>
         <div class="expiration-column">$i18n{creditCardExpiration}</div>
       </div>
       <div id="creditCardList"
           class="vertical-list list-section list-with-header">
         <template is="dom-repeat" items="[[creditCards]]">
           <div class="list-item two-line">
             <div class="type-column">
@@ skipping 33 matching lines @@
           on-tap="onMenuClearCreditCardTap_">$i18n{clearCreditCard}</button>
     </cr-shared-menu>
     <template is="dom-if" if="[[activeCreditCard]]" restamp>
       <settings-credit-card-edit-dialog credit-card="[[activeCreditCard]]"
           on-close="unstampCreditCardEditDialog_">
       </settings-credit-card-edit-dialog>
     </template>
   </template>
   <script src="/passwords_and_forms_page/autofill_section.js"></script>
 </dom-module>