Reduce webkit CSS prefixes in ui/ styles

ui/file_manager/file_manager/foreground/css/tree.css

Index: ui/file_manager/file_manager/foreground/css/tree.css
diff --git a/ui/file_manager/file_manager/foreground/css/tree.css b/ui/file_manager/file_manager/foreground/css/tree.css
index a5edc2f31e76726b359d70367f1217dd8c1c0ff0..c65967cdafc3d6ab144726a40a7cdb05d32eab52 100644
--- a/ui/file_manager/file_manager/foreground/css/tree.css
+++ b/ui/file_manager/file_manager/foreground/css/tree.css
@@ -18,8 +18,6 @@ tree {
 }
 
 .tree-row > .expand-icon {
-  transform: rotate(-90deg);
-  -webkit-transition: all 150ms;
   background-image: -webkit-image-set(
       url(../images/files/ui/expand_more.png) 1x,
       url(../images/files/ui/2x/expand_more.png) 2x);
@@ -28,6 +26,8 @@ tree {
   background-size: 16px 16px;
   vertical-align: top;
   position: relative;
+  transform: rotate(-90deg);
+  transition: all 150ms;
 }
 
 .tree-row[selected] > .expand-icon {