core: Add new unmaximize flag

Wayland clients know their size better, so for Wayland we'd rather not
try to resize the client on un-maximize, but for this to work we need a
new MetaMoveResizeFlags.

https://bugzilla.gnome.org/show_bug.cgi?id=783901

src/core/window-private.h

@@ -74,11 +74,12 @@ typedef enum {
 typedef enum
 {
   META_MOVE_RESIZE_CONFIGURE_REQUEST = 1 << 0,
-  META_MOVE_RESIZE_USER_ACTION       = 1 << 1,
+  META_MOVE_RESIZE_USER_ACTION = 1 << 1,
-  META_MOVE_RESIZE_MOVE_ACTION       = 1 << 2,
+  META_MOVE_RESIZE_MOVE_ACTION = 1 << 2,
-  META_MOVE_RESIZE_RESIZE_ACTION     = 1 << 3,
+  META_MOVE_RESIZE_RESIZE_ACTION = 1 << 3,
-  META_MOVE_RESIZE_WAYLAND_RESIZE    = 1 << 4,
+  META_MOVE_RESIZE_WAYLAND_RESIZE = 1 << 4,
-  META_MOVE_RESIZE_STATE_CHANGED     = 1 << 5,
+  META_MOVE_RESIZE_STATE_CHANGED = 1 << 5,
+  META_MOVE_RESIZE_UNMAXIMIZE = 1 << 6,
 } MetaMoveResizeFlags;
 
 typedef enum

src/core/window.c

@@ -3317,7 +3317,8 @@ meta_window_unmaximize (MetaWindow        *window,
       meta_window_move_resize_internal (window,
                                         (META_MOVE_RESIZE_MOVE_ACTION |
                                          META_MOVE_RESIZE_RESIZE_ACTION |
-                                         META_MOVE_RESIZE_STATE_CHANGED),
+                                         META_MOVE_RESIZE_STATE_CHANGED |
+                                         META_MOVE_RESIZE_UNMAXIMIZE),
                                         NorthWestGravity,
                                         target_rect);