Merge 150744 - As background-image doesn't have a notion of the size it is supposed to be, when the…

chrome/browser/resources/ntp_search/new_tab_theme.css

Index: chrome/browser/resources/ntp_search/new_tab_theme.css
===================================================================
--- chrome/browser/resources/ntp_search/new_tab_theme.css	(revision 151406)
+++ chrome/browser/resources/ntp_search/new_tab_theme.css	(working copy)
@@ -5,7 +5,8 @@
 html {
   background-attachment: fixed;
   background-color: $2;  /* COLOR_NTP_BACKGROUND */
-  background-image: url(chrome://theme/IDR_THEME_NTP_BACKGROUND?$1);
+  background-image: -webkit-image-set(
+    url(chrome://theme/IDR_THEME_NTP_BACKGROUND?$1) 1x);
   background-position: $3;
   background-repeat: $5;
 }