gtk: move surface destroy through deref

src/apprt/gtk/Surface.zig

@@ -223,7 +223,9 @@ pub fn init(self: *Surface, app: *App, opts: Options) !void {
     // GL area be moved around i.e. between a split, a tab, etc.
     // without having to be really careful about ordering to
     // prevent a destroy.
-    // TODO: unref in deinit
+    //
+    // This is unref'd in the unref() method that's called by the
+    // self.container through Elem.deinit.
     _ = c.g_object_ref_sink(@ptrCast(gl_area));
     errdefer c.g_object_unref(@ptrCast(gl_area));
 
@@ -375,11 +377,6 @@ fn realize(self: *Surface) !void {
     self.realized = true;
 }
 
-pub fn destroy(self: *Surface, alloc: Allocator) void {
-    self.deinit();
-    alloc.destroy(self);
-}
-
 pub fn deinit(self: *Surface) void {
     // We don't allocate anything if we aren't realized.
     if (!self.realized) return;

src/apprt/gtk/Tab.zig

@@ -96,7 +96,7 @@ pub fn init(self: *Tab, window: *Window, parent_: ?*CoreSurface) !void {
     var surface = try Surface.create(window.app.core_app.alloc, window.app, .{
         .parent2 = parent_,
     });
-    errdefer surface.destroy(window.app.core_app.alloc);
+    errdefer surface.unref();
     surface.setContainer(.{ .tab_ = self });
     self.elem = .{ .surface = surface };