[gnome-photos] item-manager: Emit active-collection-changed only when there's a change

[Debarshi Ray <debarshir src gnome org>]

commit 110d77b5d50234f3bc6ede96cb396301444c23ca
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Jul 28 12:02:29 2017 +0200

    item-manager: Emit active-collection-changed only when there's a change

 src/photos-item-manager.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/src/photos-item-manager.c b/src/photos-item-manager.c
index 16b0108..a5a0751 100644
--- a/src/photos-item-manager.c
+++ b/src/photos-item-manager.c
@@ -1347,12 +1347,21 @@ photos_mode_controller_go_back (PhotosModeController *self)
     }
   else if (old_mode != PHOTOS_WINDOW_MODE_EDIT)
     {
-      g_clear_object (&self->active_collection);
+      gboolean active_collection_changed = FALSE;
+
+      if (self->active_collection != NULL)
+        {
+          g_clear_object (&self->active_collection);
+          active_collection_changed = TRUE;
+        }
+
       g_clear_object (&self->active_object);
       self->load_state = PHOTOS_LOAD_STATE_NONE;
 
       g_signal_emit_by_name (self, "active-changed", self->active_object);
-      g_signal_emit (self, signals[ACTIVE_COLLECTION_CHANGED], 0, self->active_collection);
+
+      if (active_collection_changed)
+        g_signal_emit (self, signals[ACTIVE_COLLECTION_CHANGED], 0, self->active_collection);
     }
 
   g_signal_emit (self, signals[WINDOW_MODE_CHANGED], 0, self->mode, old_mode);