Hoist the style parts of sequential.rs into style/.

components/style/sequential.rs

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Implements sequential traversal over the DOM tree.
+
+use dom::TNode;
+use traversal::DomTraversalContext;
+
+pub fn traverse_dom_preorder<'ln, N, C>(root: N,
+                                        shared: &C::SharedContext)
+                                        where N: TNode<'ln>,
+                                              C: DomTraversalContext<'ln, N> {
+    fn doit<'a, 'ln, N, C>(context: &'a C, node: N)
+                           where N: TNode<'ln>, C: DomTraversalContext<'ln, N> {
+        context.process_preorder(node);
+
+        for kid in node.children() {
+            doit::<N, C>(context, kid);
+        }
+
+        context.process_postorder(node);
+    }
+
+    let context = C::new(shared, root.opaque());
+    doit::<N, C>(&context, root);
+}
+