[Sync] chrome://sync-internals uses deprecated CSS

components/sync_driver/resources/sync_search.css

Index: components/sync_driver/resources/sync_search.css
diff --git a/components/sync_driver/resources/sync_search.css b/components/sync_driver/resources/sync_search.css
index 24c955b97d6f537da429db90977dc04073948d16..5500b469fe5fb44e80f983374b46ed4d596d3927 100644
--- a/components/sync_driver/resources/sync_search.css
+++ b/components/sync_driver/resources/sync_search.css
@@ -22,7 +22,7 @@
 }
 
 #sync-results-container {
-  display: -webkit-box;
+  display: flex;
   /* Should be > #sync-page's min-height. */
   /* TODO(akalin): Find a less hacky way to do this. */
   height: 750px;
@@ -51,7 +51,7 @@
 }
 
 #sync-result-details-container {
-  -webkit-box-flex: 1;
+  flex: 1;
   height: 100%;
   overflow: auto;
   /* TODO(akalin): Figure out why this is needed, even with box-flex: 1. */