MD Settings: Fix rendering of popup menus inside iron-lists.

chrome/browser/resources/settings/search_engines_page/search_engines_page.html

Index: chrome/browser/resources/settings/search_engines_page/search_engines_page.html
diff --git a/chrome/browser/resources/settings/search_engines_page/search_engines_page.html b/chrome/browser/resources/settings/search_engines_page/search_engines_page.html
index 0cd7c510880907973b874b16ec9cc2843fcab2c0..00302cfc6eb0f2af5fdc27f520073c877edc42d9 100644
--- a/chrome/browser/resources/settings/search_engines_page/search_engines_page.html
+++ b/chrome/browser/resources/settings/search_engines_page/search_engines_page.html
@@ -25,6 +25,10 @@
       settings-omnibox-extension-entry:first-of-type {
         border-top: none;
       }
+
+      #extensions-container {
+        overflow: inherit;
+      }
     </style>
     <div class="settings-box first">
       <h2>$i18n{searchEnginesDefault}</h2>
@@ -49,14 +53,16 @@
       <div class="settings-box first">
         <h2>$i18n{searchEnginesExtension}</h2>
       </div>
-      <iron-list id="extensions" class="extension-engines" selectable
-          items="[[extensions]]">
-        <template>
-          <settings-omnibox-extension-entry engine="[[item]]"
-              tabindex$="[[tabIndex]]">
-          </settings-omnibox-extension-entry>
-        </template>
-      </iron-list>
+      <div id="extensions-container">
+        <iron-list id="extensions" class="extension-engines" selectable
+            items="[[extensions]]" scroll-target="extensions-container">
+          <template>
+            <settings-omnibox-extension-entry engine="[[item]]"
+                tabindex$="[[tabIndex]]">
+            </settings-omnibox-extension-entry>
+          </template>
+        </iron-list>
+      </div>
     </template>
   </template>
   <script src="search_engines_page.js"></script>