MD Settings: convert paper-icon-button to paper-icon-button-light.

ui/webui/resources/cr_elements/shared_style_css.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/shared_vars_css.html">
 <link rel="import" href="hidden_style_css.html">
+<link rel="import" href="cr_icons_css.html">
 
 <!-- Common styles for Material Design WebUI. Included directly in
   settings_shared_css.html. -->
 <dom-module id="cr-shared-style">
   <template>
-    <style include="cr-hidden-style">
+    <style include="cr-hidden-style cr-icons">
       :host-context([dir=rtl]) button[is='paper-icon-button-light'] {
         transform: scaleX(-1);  /* Flip on the X axis (aka mirror). */
       }
 
       /* Chrome spinners should be blue. */
       paper-spinner {
         --paper-spinner-layer-1-color: var(--google-blue-500);
         --paper-spinner-layer-2-color: var(--google-blue-500);
         --paper-spinner-layer-3-color: var(--google-blue-500);
         --paper-spinner-layer-4-color: var(--google-blue-500);
@@ skipping 22 matching lines @@
         font-weight: 500;
         line-height: 154%;
         padding: 8px 16px;
       }
 
       [actionable] {
         @apply(--cr-actionable);
       }
 
       button[is='paper-icon-button-light'] {
-        -webkit-margin-end: var(--cr-icon-ripple-margin);
-        -webkit-margin-start: 16px;
+        @apply(--cr-paper-icon-button-margin);
         background-position: center;
         background-repeat: no-repeat;
         background-size: var(--cr-icon-size);
         flex-shrink: 0;
         height: var(--cr-icon-ripple-size);
         width: var(--cr-icon-ripple-size);
       }
 
-      button[is='paper-icon-button-light'].subpage-arrow {
-        background-image: url(chrome://resources/images/arrow_right.svg);
-      }
-
-      button[is='paper-icon-button-light'].icon-cancel {
-        background-image: url(chrome://resources/images/icon_cancel.svg);
-      }
-
-      button[is='paper-icon-button-light'].icon-cancel-toolbar {
-        background-image:
-            url(chrome://resources/images/icon_cancel_toolbar.svg);
-      }
-
-      button[is='paper-icon-button-light'].icon-external {
-        background-image: url(chrome://resources/images/open_in_new.svg);
-      }
-
       .subpage-arrow,
       .icon-external {
         display: none;
       }
 
-      paper-icon-button.subpage-arrow {
-        background-image: url(../images/arrow_right.svg);
-      }
-
       [actionable] :-webkit-any(.subpage-arrow, .icon-external),
       [actionable]:-webkit-any(.subpage-arrow, .icon-external) {
         display: block;
       }
 
       [scrollable] {
         border-color: transparent;
         border-style: solid;
         border-width: 1px 0;
         overflow-y: auto;
@@ skipping 18 matching lines @@
       [selectable]:focus,
       [selectable] > :focus {
         @apply(--cr-selectable-focus);
       }
       [selectable] > * {
         @apply(--cr-actionable);
       }
     </style>
   </template>
 </dom-module>