[MD WebUI] Move icons used in Bookmarks and Settings to shared file.

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;
       }
 
       :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'] {
+      :host-context([dir=rtl]) paper-icon-button[icon='cr: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 {
         align-items: center;
         align-self: flex-start;
         color: var(--paper-grey-600);
         display: flex;
         font-size: inherit;
         font-weight: 500;
         margin: 0;
         padding-top: 24px;
         padding-bottom: 12px;
       }
 
       iron-icon[icon='cr:check'],
-      iron-icon[icon='settings:done'] {
+      iron-icon[icon='cr:done'] {
        --iron-icon-fill-color: var(--google-green-500);
       }
 
       paper-button {
         height: 32px;
         margin: 0;
       }
 
       paper-button[toggles][active] {
         background-color: var(--paper-grey-300);
@@ skipping 329 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>