Use tokenPos instead of line/col in the vm service.

runtime/bin/vmservice/client/lib/src/elements/script_inset.dart

+// Copyright (c) 2013, 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.
+
+library script_inset_element;
+
+import 'observatory_element.dart';
+import 'package:observatory/service.dart';
+import 'package:polymer/polymer.dart';
+
+/// Displays an Error response.
+@CustomTag('script-inset')
+class ScriptInsetElement extends ObservatoryElement {
+  @published Script script;
+  @published int pos;
+  bool loadStarted = false;
+
+  @observable List<ScriptLine> lines = toObservable([]);
+  
+  void scriptChanged(oldValue) {
+    loadStarted = false;

[Cutch, 2014/03/28 20:22:32]

Maybe add a TODO to move this load state tracking into ServiceObject.

+    _updateProperties();
+  }
+
+  void posChanged(oldValue) {
+    loadStarted = false;
+    _updateProperties();
+  }
+
+  void _updateProperties() {
+    if (!script.loaded) {
+      if (!loadStarted) {
+        loadStarted = true;
+        script.load().then((_) {
+            if (script.loaded) {
+              _updateProperties();
+            }
+          });
+      }
+      return;
+    }
+    notifyPropertyChange(#lines, 0, 1);
+    var lineNumber = script.tokenToLine(pos);
+    lines.clear();
+    lines.add(script.lines[lineNumber-1]);
+  }
+
+  ScriptInsetElement.created() : super.created();
+}