windowManager: Add unminimize effect

The effect was added to mutter a while ago, but never implemented
in the shell. Just do the reverse of the minimize animation ...

https://bugzilla.gnome.org/show_bug.cgi?id=702662

src/shell-wm.c

@@ -19,6 +19,7 @@ struct _ShellWM {
 enum
 {
   MINIMIZE,
+  UNMINIMIZE,
   MAXIMIZE,
   UNMAXIMIZE,
   MAP,
@@ -65,6 +66,14 @@ shell_wm_class_init (ShellWMClass *klass)
                   NULL, NULL, NULL,
                   G_TYPE_NONE, 1,
                   META_TYPE_WINDOW_ACTOR);
+  shell_wm_signals[UNMINIMIZE] =
+    g_signal_new ("unminimize",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 1,
+                  META_TYPE_WINDOW_ACTOR);
   shell_wm_signals[MAXIMIZE] =
     g_signal_new ("maximize",
                   G_TYPE_FROM_CLASS (klass),
@@ -197,6 +206,20 @@ shell_wm_completed_minimize (ShellWM         *wm,
   meta_plugin_minimize_completed (wm->plugin, actor);
 }
 
+/**
+ * shell_wm_completed_unminimize:
+ * @wm: the ShellWM
+ * @actor: the MetaWindowActor actor
+ *
+ * The plugin must call this when it has completed a window unminimize effect.
+ **/
+void
+shell_wm_completed_unminimize (ShellWM         *wm,
+                               MetaWindowActor *actor)
+{
+  meta_plugin_unminimize_completed (wm->plugin, actor);
+}
+
 /**
  * shell_wm_completed_maximize:
  * @wm: the ShellWM
@@ -328,6 +351,13 @@ _shell_wm_minimize (ShellWM         *wm,
   g_signal_emit (wm, shell_wm_signals[MINIMIZE], 0, actor);
 }
 
+void
+_shell_wm_unminimize (ShellWM         *wm,
+                      MetaWindowActor *actor)
+{
+  g_signal_emit (wm, shell_wm_signals[UNMINIMIZE], 0, actor);
+}
+
 void
 _shell_wm_maximize (ShellWM         *wm,
                     MetaWindowActor *actor,