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

chrome/browser/resources/ntp4/new_tab_theme.css

Index: chrome/browser/resources/ntp4/new_tab_theme.css
diff --git a/chrome/browser/resources/ntp4/new_tab_theme.css b/chrome/browser/resources/ntp4/new_tab_theme.css
index adfeeb7c371adb0a171cad46d0e78d72345bc50d..888eebd6a7c16c85b6ad4233642e990e8c2eecd7 100644
--- a/chrome/browser/resources/ntp4/new_tab_theme.css
+++ b/chrome/browser/resources/ntp4/new_tab_theme.css
@@ -25,12 +25,12 @@ body {
 }
 
 #attribution,
-.link-button,
+[is='action-link'],
 .link-span {
   color: $21;  /* COLOR_NTP_TEXT_LIGHT */
 }
 
-.link-button:active {
+[is='action-link']:active {
   color: $8;  /* COLOR_NTP_TEXT */
 }