Add a mode to dartdoc to generate the navigation on the client.

utils/dartdoc/client-shared.dart

Index: utils/dartdoc/client-shared.dart
diff --git a/utils/dartdoc/client-shared.dart b/utils/dartdoc/client-shared.dart
new file mode 100644
index 0000000000000000000000000000000000000000..1a9eff28c42d28a5c467ef6a4715faf9f3b4ec8a
--- /dev/null
+++ b/utils/dartdoc/client-shared.dart
@@ -0,0 +1,33 @@
+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Code shared between the different client-side libraries.
+
+/**
+ * Finds all code blocks and makes them toggleable. Syntax highlights each
+ * code block the first time it's shown.
+ */
+enableCodeBlocks() {
+  for (var elem in document.queryAll('.method, .field')) {
+    var showCode = elem.query('.show-code');
+
+    // Skip it if we don't have a code link. Will happen if source code is
+    // disabled.
+    if (showCode == null) continue;
+
+    var pre = elem.query('pre.source');
+    showCode.on.click.add((e) {
+      if (pre.classes.contains('expanded')) {
+        pre.classes.remove('expanded');
+      } else {
+        // Syntax highlight.
+        if (!pre.classes.contains('formatted')) {
+          pre.innerHTML = classifySource(new frog.SourceFile('', pre.text));
+          pre.classes.add('formatted');
+        };
+        pre.classes.add('expanded');
+      }
+    });
+  }
+}