MD Settings: Fix cookie exceptions flex layout regression.

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

 <link rel="import" href="chrome://resources/html/polymer.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/cr_elements/policy/cr_policy_pref_indicator.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout-classes.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">
 <link rel="import" href="add_site_dialog.html">
 <link rel="import" href="constants.html">
 <link rel="import" href="edit_exception_dialog.html">
 <link rel="import" href="site_settings_behavior.html">
 <link rel="import" href="site_settings_prefs_browser_proxy.html">
 
 <dom-module id="site-list">
   <template>
-    <style include="settings-shared">
+    <style include="settings-shared iron-flex">
       .selectable {
         -webkit-user-select: text;
       }
     </style>
     <div id="category">
       <div class="settings-box first" hidden$="[[allSites]]">
         <h2 class="start">[[categoryHeader]]</h2>
         <paper-button id="addSite"
             class="secondary-button header-aligned-button"
             hidden="[[readOnlyList]]" on-tap="onAddSiteTap_">
@@ skipping 24 matching lines @@
           $i18n{siteSettingsActionReset}
         </button>
       </dialog>
 
       <div class="list-frame" hidden$="[[hasSites_(sites)]]">
         <div class="list-item secondary">$i18n{noSitesAdded}</div>
       </div>
       <div class="list-frame menu-content vertical-list" id="listContainer">
         <template is="dom-repeat" items="[[sites]]">
           <div class="list-item">
             <div class="layout horizontal center flex"

[dschuyler, 2017/04/27 21:57:26]

I think "layout horizontal center flex" may be replaced with "start" and the
import of iron-flex-layout removed (if so yay to less code).

[dschuyler, 2017/04/27 22:20:54]

We just chatted about this and it's a bit more involved. Removing the need to
import the iron-flex-layout can be done later.

                 actionable$="[[enableSiteSettings_]]" on-tap="onOriginTap_">
               <div class="favicon-image"
                   style$="[[computeSiteIcon(item.origin)]]">
               </div>
               <div class="middle no-min-width">
                 <div class="selectable text-elide">[[item.displayName]]</div>
 
                 <!-- This div must not contain extra whitespace. -->
                 <div class="selectable secondary text-elide"
                     id="siteDescription">[[computeSiteDescription_(item)]]</div>
@@ skipping 32 matching lines @@
       </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>