Remove dangling chrome://theme/IDR_CLOSE_BAR* references

chrome/browser/resources/shared/css/expandable_bubble.css

Index: chrome/browser/resources/shared/css/expandable_bubble.css
diff --git a/chrome/browser/resources/shared/css/expandable_bubble.css b/chrome/browser/resources/shared/css/expandable_bubble.css
index 193abe1dc141a746d47edbee7206f15917e3977f..c17160bc8113e00dc18e78201798695ddd39368e 100644
--- a/chrome/browser/resources/shared/css/expandable_bubble.css
+++ b/chrome/browser/resources/shared/css/expandable_bubble.css
@@ -74,13 +74,13 @@
 }
 
 .expandable-bubble-close {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR');
+  background-image: url('../../../../../ui/resources/close_bar.png');
 }
 
 .expandable-bubble-close:hover {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR_H');
+  background-image: url('../../../../../ui/resources/close_bar_h.png');
 }
 
 .expandable-bubble-close:active {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR_P');
+  background-image: url('../../../../../ui/resources/close_bar_p.png');
 }