Use HighDPI asset on about:flags

chrome/browser/resources/flags.css

Index: chrome/browser/resources/flags.css
diff --git a/chrome/browser/resources/flags.css b/chrome/browser/resources/flags.css
index d9a6e0cabd255720f203ae68d18cb0791b9ef214..18caa028f0fbda30b866813287aca7376ef5d4ca 100644
--- a/chrome/browser/resources/flags.css
+++ b/chrome/browser/resources/flags.css
@@ -28,7 +28,10 @@ div#header {
 
 #header h1 {
   -webkit-padding-start: 75px;
-  background: url('../../app/theme/flags_section.png') 0 20px no-repeat;
+  background: -webkit-image-set(
+      url('../../app/theme/default_100_percent/flags_section.png') 1x,

[Dan Beam, 2013/01/07 19:39:21]

if possible I'd like to use grit to autogenerate this for us like this -
https://codereview.chromium.org/11774004 - is there a functional difference?

+      url('../../app/theme/default_200_percent/flags_section.png') 2x)
+      0 20px no-repeat;
   display: inline;
   margin: 0;
   padding-bottom: 40px;
@@ -36,7 +39,10 @@ div#header {
 }
 
 html[dir=rtl] #header h1 {
-  background: url('../../app/theme/flags_section.png') right no-repeat;
+  background: -webkit-image-set(
+      url('../../app/theme/default_100_percent/flags_section.png') 1x,
+      url('../../app/theme/default_200_percent/flags_section.png') 2x)
+      right no-repeat;
 }
 
 h1 {