[mutter] ui: Bring back the is_input_event helper

[Jasper St. Pierre <jstpierre src gnome org>]

commit 13b7fa4eba0ccee78f8ce0da5c31a01bc0fd270c
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Jul 8 12:59:25 2014 -0400

    ui: Bring back the is_input_event helper
    
    This makes the logic clearer and easier to reason about.

 src/ui/ui.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)
---
diff --git a/src/ui/ui.c b/src/ui/ui.c
index 2c2166b..dc2f4a2 100644
--- a/src/ui/ui.c
+++ b/src/ui/ui.c
@@ -75,13 +75,20 @@ meta_ui_get_screen_number (void)
 #include "display-private.h"
 
 static gboolean
-is_interesting_input_event (XEvent *event)
+is_input_event (XEvent *event)
 {
   MetaDisplay *display = meta_get_display ();
+
+  return (event->type == GenericEvent &&
+          event->xcookie.extension == display->xinput_opcode);
+}
+
+static gboolean
+is_interesting_input_event (XEvent *event)
+{
   XIEvent *input_event;
 
-  if (event->type != GenericEvent ||
-      event->xcookie.extension != display->xinput_opcode)
+  if (!is_input_event (event))
     return FALSE;
 
   input_event = (XIEvent *) event->xcookie.data;