MD Settings: settings-dropdown-menu, restore "Enter" key behavior.

chrome/browser/resources/settings/settings_shared_css.html

 <link rel="import" href="chrome://resources/cr_elements/shared_style_css.html">
 <link rel="import" href="/settings_root_css.html">
 
 <!-- Common styles for Material Design settings. -->
 <dom-module id="settings-shared">
   <template>
     <style include="cr-shared-style">
       h2 {
         align-items: center;
         display: flex;
@@ skipping 21 matching lines @@
         --paper-font-subhead: {
           font-size: inherit;
         };
         --paper-input-container-underline: {
           background: var(--paper-grey-300);
         };
       }
 
       paper-dropdown-menu .dropdown-item {
         align-items: center;
+        background: none;
+        border: none;

[Dan Beam, 2016/07/12 23:00:27]

nit: -webkit-appearance: none;

[dpapad, 2016/07/12 23:18:02]

Does not seem to work equivalently for me, see http://imgur.com/4rctYdV.

[Dan Beam, 2016/07/12 23:27:26]

we use it in widgets.css and otherwise a -webkit-appearance: push-button; is
probably applied.  maybe it's just doing a background and your rule is
overriding.  it's probably fine.

         color: var(--paper-grey-800);
         display: flex;
         font-size: inherit;

[Dan Beam, 2016/07/12 23:00:27]

do we need to change this to font: inherit?  i remember something funky about
font-face not working well with <button>s by default

[dpapad, 2016/07/12 23:18:02]

Done. Changing 'font-size' to 'font' indeed has an effect on the applied font,
from Arial to "Roboto, Ubuntu.."

         min-height: 48px;
         padding: 0 16px;
+        width: 100%;
       }
 
       paper-dropdown-menu .dropdown-item.iron-selected {
         font-weight: bold;
       }
 
       paper-dropdown-menu .dropdown-item:focus {
         background-color: var(--paper-grey-300);
         outline: none;
       }
@@ skipping 264 matching lines @@
 
       .favicon-image {
         background-repeat: no-repeat;
         background-size: contain;
         height: 16px;
         width: 16px;
       }
     </style>
   </template>
 </dom-module>