Files.app: Update filetype icons.

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 38891fc98962c7a9ac7d7af0b0f69be339bc0da5..a319a94ec1d1d46e6cf29de92a0ca7cf21770cb5 100644
--- a/ui/file_manager/file_manager/foreground/css/tree.css
+++ b/ui/file_manager/file_manager/foreground/css/tree.css
@@ -18,24 +18,29 @@ tree {
 }
 
 .tree-row > .expand-icon {
+  -webkit-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);
+  background-position: 50% 50%;
+  background-repeat: no-repeat;
+  background-size: 16px 16px;
+  vertical-align: top;
   position: relative;
 }
 
-.tree-row > .expand-icon > core-icon {
-  -webkit-transform: rotate(-90deg);
-  -webkit-transition: all 150ms;
-  height: 16px;
-  left: 10px;
-  position: absolute;
-  top: 10px;
-  width: 16px;
+.tree-row[selected] > .expand-icon {
+  background-image: -webkit-image-set(
+      url(../images/files/ui/expand_more_active.png) 1x,
+      url(../images/files/ui/2x/expand_more_active.png) 2x);
 }
 
-html[dir=rtl] .tree-row > .expand-icon > core-icon {
+html[dir=rtl] .tree-row > .expand-icon {
   -webkit-transform: rotate(90deg);
 }
 
-.tree-item[expanded] > .tree-row > .expand-icon > core-icon {
+.tree-item[expanded] > .tree-row > .expand-icon {
   -webkit-transform: rotate(0);
 }