NTP4/Sync Promo:

chrome/browser/resources/ntp4/new_tab_theme.css

 /* Copyright (c) 2011 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.
  */
 
 html,
 #most-visited-settings {
   background-attachment: fixed;
   background-color: $2;  /* COLOR_NTP_BACKGROUND */
   background-image: url(chrome://theme/IDR_THEME_NTP_BACKGROUND?$1);
@@ skipping 19 matching lines @@
   color: rgba($23, 0.5);  /* COLOR_NTP_TEXT */
 }
 
 .page-switcher:hover,
 .page-switcher:focus,
 .page-switcher.drag-target {
   background-color: rgba($23, 0.06);  /* COLOR_NTP_TEXT */
 }
 
 /* Only change the background to a gradient when a promo is showing. */
-.showing-sync-promo #page-switcher-end:hover,
-.showing-sync-promo #page-switcher-end:focus,
-.showing-sync-promo #page-switcher-end.drag-target {
+.showing-login-area #page-switcher-end:hover,
+.showing-login-area #page-switcher-end:focus,
+.showing-login-area #page-switcher-end.drag-target {
   background:
       -webkit-linear-gradient(top, rgba($23, 0) 0,
                                    rgba($23, .01) 60px,
                                    rgba($23, .06) 183px);  /* COLOR_NTP_TEXT */
 }
 
 .tile-page-scrollbar {
   background-color: $21;  /* COLOR_NTP_TEXT_LIGHT */
 }
 
@@ skipping 55 matching lines @@
 }
 
 .thumbnail-wrapper {
   /* This shows through at the (rounded) thumbnail's corners. */
   background-color: $11;  /* COLOR_NTP_SECTION_BORDER */
 }
 
 .filler .thumbnail {
   border-color: $2;  /* COLOR_NTP_BACKGROUND */
 }