Update the subdir icon to svg.

BUG=21705832

Change-Id: I400b5402c0efd34d79be3e8b05b2154dd8c48735
(cherry picked from commit 032c283ef3)

packages/DocumentsUI/res/drawable/ic_subdirectory_arrow.xml

@@ -1,5 +1,24 @@
-<?xml version="1.0" encoding="utf-8"?>
-<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
-    android:src="@drawable/ic_subdirectory_arrow_am_alpha"
-    android:tint="?android:attr/colorControlNormal"
-    android:autoMirrored="true" />
+<!--
+Copyright (C) 2016 The Android Open Source Project
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="?android:attr/colorControlNormal"
+        android:pathData="M19 15l-6 6,-1.42,-1.42L15.17 16H4V4h2v10h9.17l-3.59,-3.58L13 9l6 6z"/>
+</vector>

packages/DocumentsUI/res/layout/item_subdir.xml

@@ -26,8 +26,8 @@
 
     <ImageView
         android:id="@+id/subdir"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
+        android:layout_width="24dp"
+        android:layout_height="24dp"
         android:paddingEnd="8dp"
         android:scaleType="centerInside"
         android:visibility="gone"