Remove dangling chrome://theme/IDR_CLOSE_BAR* references

chrome/browser/resources/ntp4/new_tab.css

Index: chrome/browser/resources/ntp4/new_tab.css
diff --git a/chrome/browser/resources/ntp4/new_tab.css b/chrome/browser/resources/ntp4/new_tab.css
index 2f0d56d1b6d5e2110f23657eaf9e85811e687c6c..6470457a3131734315a77af1be1af941bb4d9a2b 100644
--- a/chrome/browser/resources/ntp4/new_tab.css
+++ b/chrome/browser/resources/ntp4/new_tab.css
@@ -66,7 +66,7 @@ body {
   background: no-repeat;
   background-color: transparent;
   /* TODO(estade): this should animate between states. */
-  background-image: url('chrome://theme/IDR_CLOSE_BAR');
+  background-image: url('../../../../ui/resources/close_bar.png');
   border: 0;
   cursor: default;
   display: inline-block;
@@ -77,11 +77,11 @@ body {
 
 .close-button:hover,
 .close-button:focus {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR_H');
+  background-image: url('../../../../ui/resources/close_bar_h.png');
 }
 
 .close-button:active {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR_P');
+  background-image: url('../../../../ui/resources/close_bar_p.png');
 }
 
 .linkButton {