[gtk/gtk-3-24] gdk: Add a private api to find sandboxes

[Matthias Clasen <matthiasc src gnome org>]

commit 929a19ca89a67553b13bee3da574d4499d457b92
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon May 28 12:04:17 2018 -0400

    gdk: Add a private api to find sandboxes
    
    This will be used in more places in the future.

 gdk/gdk-private.h |  2 ++
 gdk/gdk.c         | 14 +++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)
---
diff --git a/gdk/gdk-private.h b/gdk/gdk-private.h
index 69d126638f..e292429fd4 100644
--- a/gdk/gdk-private.h
+++ b/gdk/gdk-private.h
@@ -77,4 +77,6 @@ typedef struct {
 GDK_AVAILABLE_IN_ALL
 GdkPrivateVTable *      gdk__private__  (void);
 
+gboolean gdk_running_in_sandbox (void);
+
 #endif /* __GDK__PRIVATE_H__ */
diff --git a/gdk/gdk.c b/gdk/gdk.c
index 22d7841815..d2e82ccc5b 100644
--- a/gdk/gdk.c
+++ b/gdk/gdk.c
@@ -468,6 +468,19 @@ gdk_display_open_default (void)
   return display;
 }
 
+gboolean
+gdk_running_in_sandbox (void)
+{
+  char *path;
+  gboolean ret;
+
+  path = g_build_filename (g_get_user_runtime_dir (), "flatpak-info", NULL);
+  ret = g_file_test (path, G_FILE_TEST_EXISTS);
+  g_free (path);
+
+  return ret;
+}
+
 /**
  * gdk_display_open_default_libgtk_only:
  *
@@ -601,7 +614,6 @@ gdk_init (int *argc, char ***argv)
  * management for you.
  */
 
-
 /**
  * gdk_threads_enter:
  *