Backed out changeset e288814a44ef (bug 1397956) for debug build bustage on Linux, build bustage on Windows and many test failures, especially on Android. r=backout on a CLOSED TREE

modules/libpref/init/all.js

@@ -3338,7 +3338,7 @@ pref("dom.ipc.processCount.file", 1);
 pref("dom.ipc.processCount.extension", 1);
 
 // Don't use a native event loop in the content process.
-pref("dom.ipc.useNativeEventProcessing.content", true);
+pref("dom.ipc.useNativeEventProcessing.content", false);
 
 // Quantum DOM scheduling:
 pref("dom.ipc.scheduler", false);