application: Only add CSS providers once

Instead of adding the color CSS provider over and over on
every activation, only add it once. Also make sure to start
the manager after doing that.

src/gui/gcal-application.c

@@ -369,16 +369,6 @@ gcal_application_activate (GApplication *application)
 
   self = GCAL_APPLICATION (application);
 
-  if (!self->provider)
-    load_css_provider (self);
-
-  if (self->colors_provider)
-    {
-      gtk_style_context_add_provider_for_screen (gdk_screen_get_default (),
-                                                 GTK_STYLE_PROVIDER (self->colors_provider),
-                                                 GTK_STYLE_PROVIDER_PRIORITY_APPLICATION + 2);
-    }
-
   if (!self->window)
     {
       if (!self->initial_date)
@@ -438,11 +428,6 @@ gcal_application_startup (GApplication *app)
 
   G_APPLICATION_CLASS (gcal_application_parent_class)->startup (app);
 
-  self->colors_provider = gtk_css_provider_new ();
-
-  /* Startup the manager */
-  gcal_context_startup (self->context);
-
   /* We're assuming the application is called as a service only by the shell search system */
   if ((g_application_get_flags (app) & G_APPLICATION_IS_SERVICE) != 0)
     g_application_set_inactivity_timeout (app, 3 * 60 * 1000);
@@ -450,6 +435,17 @@ gcal_application_startup (GApplication *app)
   /*  initialize libhandy */
   hdy_init();
 
+  /* CSS */
+  load_css_provider (self);
+
+  self->colors_provider = gtk_css_provider_new ();
+  gtk_style_context_add_provider_for_screen (gdk_screen_get_default (),
+                                             GTK_STYLE_PROVIDER (self->colors_provider),
+                                             GTK_STYLE_PROVIDER_PRIORITY_APPLICATION + 2);
+
+  /* Startup the manager */
+  gcal_context_startup (self->context);
+
   GCAL_EXIT;
 }