Add <a is="action-link">, a web component extension of <a> for in-page actions.

ui/webui/resources/css/widgets.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 /* This file defines styles for form controls. The order of rule blocks is
  * important as there are some rules with equal specificity that rely on order
  * as a tiebreaker. These are marked with OVERRIDE. */
 
 /* Default state **************************************************************/
 
 :-webkit-any(button,
              input[type='button'],
-             input[type='submit']):not(.custom-appearance):not(.link-button),
+             input[type='submit']):not(.custom-appearance),
 select,
 input[type='checkbox'],
 input[type='radio'] {
   -webkit-appearance: none;
   -webkit-user-select: none;
   background-image: -webkit-linear-gradient(#ededed, #ededed 38%, #dedede);
   border: 1px solid rgba(0, 0, 0, 0.25);
   border-radius: 2px;
   box-shadow: 0 1px 0 rgba(0, 0, 0, 0.08),
       inset 0 1px 2px rgba(255, 255, 255, 0.75);
   color: #444;
   font: inherit;
   margin: 0 1px 0 0;
   outline: none;
   text-shadow: 0 1px 0 rgb(240, 240, 240);
 }
 
 :-webkit-any(button,
              input[type='button'],
-             input[type='submit']):not(.custom-appearance):not(.link-button),
+             input[type='submit']):not(.custom-appearance),
 select {
   min-height: 2em;
   min-width: 4em;
 <if expr="is_win">
   /* The following platform-specific rule is necessary to get adjacent
    * buttons, text inputs, and so forth to align on their borders while also
    * aligning on the text's baselines. */
   padding-bottom: 1px;
 </if>
 }
 
 :-webkit-any(button,
              input[type='button'],
-             input[type='submit']):not(.custom-appearance):not(.link-button) {
+             input[type='submit']):not(.custom-appearance) {
   -webkit-padding-end: 10px;
   -webkit-padding-start: 10px;
 }
 
 select {
   -webkit-appearance: none;
   -webkit-padding-end: 20px;
   -webkit-padding-start: 6px;
   /* OVERRIDE */
   background-image: url('../images/select.png'),
@@ skipping 92 matching lines @@
 
 /* Hover **********************************************************************/
 
 :enabled:hover:-webkit-any(
     select,
     input[type='checkbox'],
     input[type='radio'],
     :-webkit-any(
         button,
         input[type='button'],
-        input[type='submit']):not(.custom-appearance):not(.link-button)) {
+        input[type='submit']):not(.custom-appearance)) {
   background-image: -webkit-linear-gradient(#f0f0f0, #f0f0f0 38%, #e0e0e0);
   border-color: rgba(0, 0, 0, 0.3);
   box-shadow: 0 1px 0 rgba(0, 0, 0, 0.12),
       inset 0 1px 2px rgba(255, 255, 255, 0.95);
   color: black;
 }
 
 :enabled:hover:-webkit-any(select) {
   /* OVERRIDE */
   background-image: url('../images/select.png'),
       -webkit-linear-gradient(#f0f0f0, #f0f0f0 38%, #e0e0e0);
 }
 
 /* Active *********************************************************************/
 
 :enabled:active:-webkit-any(
     select,
     input[type='checkbox'],
     input[type='radio'],
     :-webkit-any(
         button,
         input[type='button'],
-        input[type='submit']):not(.custom-appearance):not(.link-button)) {
+        input[type='submit']):not(.custom-appearance)) {
   background-image: -webkit-linear-gradient(#e7e7e7, #e7e7e7 38%, #d7d7d7);
   box-shadow: none;
   text-shadow: none;
 }
 
 :enabled:active:-webkit-any(select) {
   /* OVERRIDE */
   background-image: url('../images/select.png'),
       -webkit-linear-gradient(#e7e7e7, #e7e7e7 38%, #d7d7d7);
 }
 
 /* Disabled *******************************************************************/
 
 :disabled:-webkit-any(
     button,
     input[type='button'],
-    input[type='submit']):not(.custom-appearance):not(.link-button),
+    input[type='submit']):not(.custom-appearance),
 select:disabled {
   background-image: -webkit-linear-gradient(#f1f1f1, #f1f1f1 38%, #e6e6e6);
   border-color: rgba(80, 80, 80, 0.2);
   box-shadow: 0 1px 0 rgba(80, 80, 80, 0.08),
       inset 0 1px 2px rgba(255, 255, 255, 0.75);
   color: #aaa;
 }
 
 select:disabled {
   /* OVERRIDE */
@@ skipping 22 matching lines @@
     input[type='number'],
     input[type='password'],
     input[type='radio'],
     input[type='search'],
     input[type='text'],
     input[type='url'],
     input:not([type]),
     :-webkit-any(
          button,
          input[type='button'],
-         input[type='submit']):not(.custom-appearance):not(.link-button)) {
+         input[type='submit']):not(.custom-appearance)) {
   /* OVERRIDE */
   -webkit-transition: border-color 200ms;
   /* We use border color because it follows the border radius (unlike outline).
    * This is particularly noticeable on mac. */
   border-color: rgb(77, 144, 254);
   outline: none;
 }
 
-/* Link buttons ***************************************************************/
+/* Action links ***************************************************************/

[aboxhall, 2014/10/22 21:33:31]

Theoretically you could poke the style into the shadow root of the element in
its created callback, however since you don't need a shadow root otherwise
that's probably unnecessarily expensive. Just a thought :)

[Dan Beam, 2014/10/23 03:05:44]

right, saving until there's more fancy stuff we need to do (that otherwise
requires a shadow root)

 
-.link-button {
-  -webkit-box-shadow: none;
-  background: transparent none;
-  border: none;
-  color: rgb(17, 85, 204);
+[is='action-link'] {
   cursor: pointer;
-  /* Input elements have -webkit-small-control which can override the body font.
-   * Resolve this by using 'inherit'. */
-  font: inherit;
-  margin: 0;
-  padding: 0;
 }
 
-.link-button:hover {
+[is='action-link'] {
+  text-decoration: none;
+}
+
+[is='action-link']:hover {
   text-decoration: underline;
 }
 
-.link-button:active {
+[is='action-link']:active {
   color: rgb(5, 37, 119);
   text-decoration: underline;
 }
 
-.link-button[disabled] {
+[is='action-link'][disabled] {
   color: #999;
   cursor: default;
   text-decoration: none;
 }
 
 /* Checkbox/radio helpers ******************************************************
  *
  * .checkbox and .radio classes wrap labels. Checkboxes and radios should use
  * these classes with the markup structure:
  *
@@ skipping 19 matching lines @@
   display: block;
 }
 
 :-webkit-any(.checkbox, .radio) label:hover {
   color: black;
 }
 
 label > input:disabled:-webkit-any([type='checkbox'], [type='radio']) ~ span {
   color: #999;
 }