pt 1 in reviving the android build (copied from pm 28a1, wish me luck)

mobile/android/base/resources/drawable/action_bar_button_negative.xml

@@ -0,0 +1,20 @@
+<?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/. -->
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item android:state_pressed="false">
+        <shape>
+            <solid android:color="@color/toolbar_menu_dark_grey" />
+        </shape>
+    </item>
+
+    <item android:state_pressed="true">
+        <shape>
+            <solid android:color="@color/toolbar_grey_pressed" />
+        </shape>
+    </item>
+
+</selector>