Bug 1317600: [DateTimePicker] Spinner arrow buttons shouldn't depend on find bar resources

toolkit/themes/shared/icons/spinner-arrows.svg

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<svg xmlns="http://www.w3.org/2000/svg" width="10" height="6" viewBox="0 0 10 6">
+  <style>
+    path:not(:target) {
+      display: none;
+    }
+  </style>
+  <path id="down" d="M0 1l1-1 4 4 4-4 1 1-5 5"/>
+  <path id="up" d="M0 5l1 1 4-4 4 4 1-1-5-5"/>
+</svg>