MD Settings: Fix <settings-dialog> resizing behavior.

chrome/browser/resources/settings/settings_dialog.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-dialog-behavior/paper-dialog-behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-dialog-behavior/paper-dialog-shared-styles.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 
 <dom-module id="settings-dialog">
   <template>
     <style include="paper-dialog-shared-styles"></style>
     <style>
@@ skipping 18 matching lines @@
         align-items: center;
         border-bottom: 1px solid var(--paper-grey-300);
         display: flex;
         padding-bottom: 5px;
         padding-top: 5px;
       }
 
       :host {
         max-width: 800px;
         min-width: 500px;
+        overflow: auto;
       }
 
       :host ::content .body {
         margin-bottom: 35px;
       }
 
       :host ::content .button-container {
         display: flex;
         justify-content: flex-end;
       }
@@ skipping 40 matching lines @@
         <content select=".body"></content>
         <content select=".button-container"></content>
       </div>
     </div>
     <div class="footer-container">
       <content select=".footer"></content>
     </div>
   </template>
   <script src="settings_dialog.js"></script>
 </dom-module>