Bug 1331109 - Enable GPU process on Android. r=gfx-reviewers,aosmond

Differential Revision: https://phabricator.services.mozilla.com/D138144

modules/libpref/init/StaticPrefList.yaml

@@ -6990,7 +6990,7 @@
 
 - name: layers.gpu-process.enabled
   type: bool
-#if defined(XP_WIN)
+#if defined(XP_WIN) || defined(MOZ_WIDGET_ANDROID)
   value: true
 #else
   value: false