MD Settings / User Manager: fix blurry avatar icons

ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.js

Index: ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.js
diff --git a/ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.js b/ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.js
index cbb55e648b7e989fdca0ddf17388d0950d16bdc9..5763ff2b8d72e495c0b8f432d1929c10feb0d4ee 100644
--- a/ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.js
+++ b/ui/webui/resources/cr_elements/cr_profile_avatar_selector/cr_profile_avatar_selector.js
@@ -31,5 +31,14 @@ Polymer({
       type: Array,
       value: function() { return []; }
     }
-  }
+  },
+
+  /**
+   * @param {string} iconUrl
+   * @return {string} A CSS imageset for multiple scale factors.
+   * @private
+   */
+  getIconImageset_: function(iconUrl) {
+    return cr.icon.getProfileAvatarIcon(iconUrl);
+  },
 });