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

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

 <link rel="import" href="chrome://resources/cr_elements/icons.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/iron-list/iron-list.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_scrollable_behavior.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_shared_menu/cr_shared_menu.html">
 <link rel="import" href="/passwords_and_forms_page/password_edit_dialog.html">
 <link rel="import" href="/passwords_and_forms_page/passwords_shared_css.html">
 <link rel="import" href="/prefs/prefs.html">
 <link rel="import" href="/settings_shared_css.html">
 
 <dom-module id="passwords-section">
   <!-- action_link.css is needed for the |managePasswordsLabel| link -->
   <link rel="import" type="css" href="chrome://resources/css/action_link.css">
   <template>
     <style include="settings-shared passwords-shared">
-      #manageLink {
-        margin-bottom: 24px;
-      }
-
       #password {
         background-color: transparent;
         border: none;
         flex: 1;
         height: 20px;
         width: 0;
       }
 
       #autosigninCheckbox {
         margin-bottom: 24px;
@@ skipping 22 matching lines @@
       .menu-item {
         @apply(--settings-actionable);
       }
     </style>
     <settings-checkbox id="autosigninCheckbox"
         pref="{{prefs.credentials_enable_autosignin}}"
         label="$i18n{passwordsAutosigninLabel}"
         sub-label="$i18n{passwordsAutosigninDescription}">
     </settings-checkbox>
     <div id="manageLink">$i18nRaw{managePasswordsLabel}</div>
-    <div class="heading">$i18n{savedPasswordsHeading}</div>
+    <h2>$i18n{savedPasswordsHeading}</h2>
     <div class="item-list" scrollable>
       <div class="list-item column-header">
         <div class="website-column">$i18n{editPasswordWebsiteLabel}</div>
         <div class="username-column">
           $i18n{editPasswordUsernameLabel}
         </div>
         <div class="password-column">
           $i18n{editPasswordPasswordLabel}
         </div>
       </div>
@@ skipping 27 matching lines @@
           on-tap="onMenuEditPasswordTap_"
           hidden="[[!showPasswords]]">$i18n{passwordViewDetails}</button>
       <button id="menuRemovePassword" class="list-item menu-item"
           on-tap="onMenuRemovePasswordTap_">$i18n{removePassword}</button>
     </cr-shared-menu>
     <template is="dom-if" if="[[activePassword]]" restamp>
       <password-edit-dialog on-close="unstampPasswordEditDialog_"
           item="[[activePassword]]">
       </password-edit-dialog>
     </template>
-    <div class="heading">$i18n{passwordExceptionsHeading}</div>
+    <h2>$i18n{passwordExceptionsHeading}</h2>

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

Extra space here also.

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

Acknowledged.

     <div id="passwordExceptionsList"
         class="vertical-list list-section item-list">
       <template is="dom-repeat" items="[[passwordExceptions]]"
           filter="[[passwordExceptionFilter_(filter)]]">
         <div class="list-item two-line">
           <div class="start">
             <a id="exception" href="[[item.linkUrl]]" target="_blank"
                 class="selectable">[[item.exceptionUrl]]</a>
           </div>
           <paper-icon-button id="removeExceptionButton"
               icon="cr:close" on-tap="onRemoveExceptionButtonTap_"
               tabindex$="[[tabIndex]]"
               alt="$i18n{deletePasswordException}">
           </paper-icon-button>
         </div>
       </template>
     </div>
   </template>
   <script src="/passwords_and_forms_page/passwords_section.js"></script>
 </dom-module>