MD Settings: Fix size and padding of expand button

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_vars_css.html">
 
 <!-- Common styles for Material Design settings. -->
 <dom-module id="settings-shared">
   <template>
     <style include="cr-shared-style">
       /* Included here so we don't have to include "iron-positioning" in every
        * stylesheet. See crbug.com/498405. */
       [hidden] {
         display: none !important;
       }
 
-      button[is='paper-icon-button-light'] {
-        -webkit-margin-end: -8px;  /* Allow ripple to overlap the end. */
-        -webkit-margin-start: 16px;
-        background-position: center;
-        background-repeat: no-repeat;
-        background-size: var(--settings-icon-size);
-        flex-shrink: 0;
-        height: var(--settings-icon-ripple-size);
-        width: var(--settings-icon-ripple-size);
-      }
-
       :host-context([dir=rtl]) button[is='paper-icon-button-light'] {
         transform: scaleX(-1);  /* Flip on the X axis (aka mirror). */
       }
 
       :host-context([dir=rtl]) paper-icon-button[icon='settings:arrow-back'] {
         transform: scaleX(-1);  /* Flip on the X axis (aka mirror). */
       }
 
       /* Use <h2> as the "sub-header" mentioned in the UX design docs. */
       h2 {
@@ skipping 375 matching lines @@
       /* Turns the arrow direction downwards, when the bubble is placed above
        * the anchor element */
       .search-bubble-innards.above::after {
         -webkit-transform: rotate(-135deg);
         bottom: -5px;
         top: auto;
       }
     </style>
   </template>
 </dom-module>