cssprovider: Have a section when parsing style properties

Signal handlers expect a section to be present, so provide them with
one.

New testcase included.

https://bugzilla.gnome.org/show_bug.cgi?id=757240

testsuite/gtk/Makefile.am

@@ -41,6 +41,7 @@ TEST_PROGS += 			\
 	cellarea		\
 	check-icon-names	\
 	clipboard		\
+	cssprovider		\
 	defaultvalue		\
 	entry			\
 	expander		\

testsuite/gtk/cssprovider.c

@@ -0,0 +1,63 @@
+#include <gtk/gtk.h>
+
+static void
+assert_section_is_not_null (GtkCssProvider *provider,
+                            GtkCssSection  *section,
+                            const GError   *error,
+                            gpointer        unused)
+{
+  g_assert (section != NULL);
+}
+
+static void
+test_section_in_load_from_data (void)
+{
+  GtkCssProvider *provider;
+
+  provider = gtk_css_provider_new ();
+  g_signal_connect (provider, "parsing-error",
+                    G_CALLBACK (assert_section_is_not_null), NULL);
+  gtk_css_provider_load_from_data (provider, "random garbage goes here", -1, NULL);
+  g_object_unref (provider);
+}
+
+static void
+test_section_in_style_property (void)
+{
+  GtkCssProvider *provider;
+  GtkWidgetClass *widget_class;
+  GtkWidgetPath *path;
+  GParamSpec *pspec;
+  GValue value = G_VALUE_INIT;
+
+  provider = gtk_css_provider_new ();
+  g_signal_connect (provider, "parsing-error",
+                    G_CALLBACK (assert_section_is_not_null), NULL);
+  gtk_css_provider_load_from_data (provider, "* { -GtkWidget-interior-focus: random garbage goes here; }", -1, NULL);
+
+  widget_class = g_type_class_ref (GTK_TYPE_WIDGET);
+  pspec = gtk_widget_class_find_style_property (widget_class, "interior-focus");
+  g_assert (pspec);
+  path = gtk_widget_path_new ();
+  gtk_widget_path_append_type (path, GTK_TYPE_WIDGET);
+
+G_GNUC_BEGIN_IGNORE_DEPRECATIONS;
+  gtk_style_provider_get_style_property (GTK_STYLE_PROVIDER (provider), path, 0, pspec, &value);
+G_GNUC_END_IGNORE_DEPRECATIONS;
+
+  gtk_widget_path_unref (path);
+  g_type_class_unref (widget_class);
+  g_object_unref (provider);
+}
+
+int
+main (int argc, char *argv[])
+{
+  gtk_init (NULL, NULL);
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/cssprovider/section-in-load-from-data", test_section_in_load_from_data);
+  g_test_add_func ("/cssprovider/section-in-style-property", test_section_in_style_property);
+
+  return g_test_run ();
+}