windowManager: Replace custom shader with builtin ClutterEffects

While modal dialogs were attached to the parent's titlebar, it
made sense to leave the top of the parent window at full color.
With the new position of modal dialogs, it makes more sense to dim
the entire parent window, so we can use a combination of Clutter's
BrightnessContrast- and DesaturateEffect instead of our own custom
shader.

https://bugzilla.gnome.org/show_bug.cgi?id=674499

src/shell-util.c

@@ -773,34 +773,6 @@ shell_parse_search_provider (const char    *data,
   return FALSE;
 }
 
-/**
- * shell_shader_effect_set_double_uniform:
- * @effect: The #ClutterShaderEffect
- * @name: The name of the uniform
- * @value: The value to set it to.
- *
- * Set a double uniform on a ClutterShaderEffect.
- *
- * The problem here is that JavaScript doesn't have more than
- * one number type, and gjs tries to automatically guess what
- * type we want to set a GValue to. If the number is "1.0" or
- * something, it will use an integer, which will cause errors
- * in GLSL.
- */
-void
-shell_shader_effect_set_double_uniform (ClutterShaderEffect *effect,
-                                        const gchar         *name,
-                                        gdouble             value)
-{
-  GValue gvalue = G_VALUE_INIT;
-  g_value_init (&gvalue, G_TYPE_DOUBLE);
-  g_value_set_double (&gvalue, value);
-
-  clutter_shader_effect_set_uniform_value (effect,
-                                           name,
-                                           &gvalue);
-}
-
 /**
  * shell_session_is_active_for_systemd:
  *

src/shell-util.h

@@ -39,10 +39,6 @@ gboolean shell_parse_search_provider           (const char       *data,
                                                 char            **icon_data_uri,
                                                 GError          **error);
 
-void shell_shader_effect_set_double_uniform (ClutterShaderEffect *effect,
-                                             const gchar         *name,
-                                             gdouble             value);
-
 gboolean shell_session_is_active_for_systemd (void);
 
 gboolean shell_util_wifexited                  (int               status,