[gnome-documents] preview: Ignore motion-notify-events coming from touchscreens

[Debarshi Ray <debarshir src gnome org>]

commit c06bd53d0e49cf367e884032e4ae89ccadf2463a
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Feb 25 18:16:54 2015 +0100

    preview: Ignore motion-notify-events coming from touchscreens
    
    The EvView reacts to pan and zoom gestures. We should let the gestures
    do their thing and not reveal the overlaid controls when a user is
    moving her fingers across the touchscreen.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=741564

 src/preview.js |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/src/preview.js b/src/preview.js
index 78b1d8b..af096f3 100644
--- a/src/preview.js
+++ b/src/preview.js
@@ -654,11 +654,16 @@ const PreviewNavControls = new Lang.Class({
         return false;
     },
 
-    _onMotion: function() {
+    _onMotion: function(widget, event) {
         if (this._motionId != 0) {
             return false;
         }
 
+        let device = event.get_source_device();
+        if (device.input_source == Gdk.InputSource.TOUCHSCREEN) {
+            return false;
+        }
+
         this._motionId = Mainloop.idle_add(Lang.bind(this, this._motionTimeout));
         return false;
     },