packages/DocumentsUI/res/drawable/ic_doc_generic.xml

<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
    android:src="@drawable/ic_doc_generic_am_alpha"
    android:tint="?android:attr/colorControlNormal"
    android:autoMirrored="true" />