[epiphany] downloads-manager: Add another assert

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 7221b573a6f90b37cc3329a505627d81e0f0b808
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed Feb 15 11:34:12 2017 -0600

    downloads-manager: Add another assert
    
    Something is wrong here. This assert will help catch it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778653

 embed/ephy-downloads-manager.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/embed/ephy-downloads-manager.c b/embed/ephy-downloads-manager.c
index d7a21f1..1c166b6 100644
--- a/embed/ephy-downloads-manager.c
+++ b/embed/ephy-downloads-manager.c
@@ -49,7 +49,8 @@ G_DEFINE_TYPE (EphyDownloadsManager, ephy_downloads_manager, G_TYPE_OBJECT)
 static void
 ephy_downloads_manager_acquire_session_inhibitor (EphyDownloadsManager *manager)
 {
-  if (++manager->inhibitors > 1)
+  manager->inhibitors++;
+  if (manager->inhibitors > 1)
     return;
 
   g_assert (manager->inhibitor_cookie == 0);
@@ -65,7 +66,10 @@ ephy_downloads_manager_acquire_session_inhibitor (EphyDownloadsManager *manager)
 static void
 ephy_downloads_manager_release_session_inhibitor (EphyDownloadsManager *manager)
 {
-  if (--manager->inhibitors > 0)
+  g_assert (manager->inhibitors > 0);
+  manager->inhibitors--;
+
+  if (manager->inhibitors > 0)
     return;
 
   if (manager->inhibitor_cookie > 0) {