app: don't additionally ref the standard data objects

Instead, set their statically remembered pointer as a weak pointer so
it's nullified automatically if they are ever finalized. Doesn't
actually get rid of them upon exit yet, this is just a preparation.

app/core/gimpbrush.c

@@ -421,7 +421,8 @@ gimp_brush_get_standard (GimpContext *context)
       gimp_data_clean (standard_brush);
       gimp_data_make_internal (standard_brush, "gimp-brush-standard");
 
-      g_object_ref (standard_brush);
+      g_object_add_weak_pointer (G_OBJECT (standard_brush),
+                                 (gpointer *) &standard_brush);
     }
 
   return standard_brush;

app/core/gimpdynamics.c

@@ -422,7 +422,8 @@ gimp_dynamics_get_standard (GimpContext *context)
       gimp_data_clean (standard_dynamics);
       gimp_data_make_internal (standard_dynamics, "gimp-dynamics-standard");
 
-      g_object_ref (standard_dynamics);
+      g_object_add_weak_pointer (G_OBJECT (standard_dynamics),
+                                 (gpointer *) &standard_dynamics);
     }
 
   return standard_dynamics;

app/core/gimpgradient.c

@@ -351,7 +351,8 @@ gimp_gradient_get_standard (GimpContext *context)
       gimp_data_clean (standard_gradient);
       gimp_data_make_internal (standard_gradient, "gimp-gradient-standard");
 
-      g_object_ref (standard_gradient);
+      g_object_add_weak_pointer (G_OBJECT (standard_gradient),
+                                 (gpointer *) &standard_gradient);
     }
 
   return standard_gradient;

app/core/gimppalette.c

@@ -295,7 +295,8 @@ gimp_palette_get_standard (GimpContext *context)
       gimp_data_clean (standard_palette);
       gimp_data_make_internal (standard_palette, "gimp-palette-standard");
 
-      g_object_ref (standard_palette);
+      g_object_add_weak_pointer (G_OBJECT (standard_palette),
+                                 (gpointer *) &standard_palette);
     }
 
   return standard_palette;

app/core/gimppattern.c

@@ -249,7 +249,8 @@ gimp_pattern_get_standard (GimpContext *context)
       gimp_data_clean (standard_pattern);
       gimp_data_make_internal (standard_pattern, "gimp-pattern-standard");
 
-      g_object_ref (standard_pattern);
+      g_object_add_weak_pointer (G_OBJECT (standard_pattern),
+                                 (gpointer *) &standard_pattern);
     }
 
   return standard_pattern;

app/core/gimptoolpreset.c

@@ -446,7 +446,8 @@ gimp_tool_preset_get_standard (GimpContext *context)
       gimp_data_clean (standard_tool_preset);
       gimp_data_make_internal (standard_tool_preset, "gimp-tool-preset-standard");
 
-      g_object_ref (standard_tool_preset);
+      g_object_add_weak_pointer (G_OBJECT (standard_tool_preset),
+                                 (gpointer *) &standard_tool_preset);
     }
 
   return standard_tool_preset;