Fix issues that broke editing on browsers without Shadow DOM support.

dart/site/try/src/shadow_root.dart

Index: dart/site/try/src/shadow_root.dart
diff --git a/dart/site/try/src/shadow_root.dart b/dart/site/try/src/shadow_root.dart
index b14afc6594e29495a7d56e8bf23ab8afc0d94368..b84b77eba2a70809b11c743b76cb5bc73c195059 100644
--- a/dart/site/try/src/shadow_root.dart
+++ b/dart/site/try/src/shadow_root.dart
@@ -12,6 +12,10 @@ import 'selection.dart' show
 import 'html_to_text.dart' show
     htmlToText;
 
+const int WALKER_NEXT = 0;
+const int WALKER_RETURN = 1;
+const int WALKER_SKIP_NODE = 2;
+
 void setShadowRoot(Element node, text) {
   if (text is String) {
     text = new Text(text);
@@ -53,3 +57,39 @@ String getText(Element node) {
       node, buffer, new TrySelection.empty(node), treatRootAsInline: true);
   return '$buffer';
 }
+
+/// Position [walker] at the last predecessor (that is, child of child of
+/// child...) of [node]. The next call to walker.nextNode will return the first
+/// node after [node].
+void skip(Node node, TreeWalker walker) {
+  if (walker.nextSibling() != null) {
+    walker.previousNode();
+    return;
+  }
+  for (Node current = walker.nextNode();
+       current != null;
+       current = walker.nextNode()) {
+    if (!node.contains(current)) {
+      walker.previousNode();
+      return;
+    }
+  }
+}
+
+/// Call [f] on each node in [root] in same order as [TreeWalker].  Skip any
+/// nodes used to implement shadow root polyfill.
+void walkNodes(Node root, int f(Node node)) {
+  TreeWalker walker = new TreeWalker(root, NodeFilter.SHOW_ALL);
+
+  for (Node node = root; node != null; node = walker.nextNode()) {
+    if (!ShadowRoot.supported &&
+        node is Element &&
+        node.getAttribute('try-dart-shadow-root') != null) {
+      skip(node, walker);
+    }
+    int action = f(node);
+    if (action == WALKER_RETURN) return;
+    if (action == WALKER_SKIP_NODE) skip(node, walker);

[Johnni Winther, 2014/07/02 08:40:54]

'continue' after skip to avoid the assertion of `action == WALKER_NEXT` ?

[ahe, 2014/07/04 13:52:00]

I turned it into a switch.

+    assert(action == WALKER_NEXT);
+  }
+}