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

runtime/bin/vmservice/client/lib/src/elements/script_ref.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_ref_element;
 
 import 'package:polymer/polymer.dart';
+import 'package:observatory/service.dart';
 import 'service_ref.dart';
 
 @CustomTag('script-ref')
 class ScriptRefElement extends ServiceRefElement {
-  @published int line = -1;
+  @published int pos = -1;
+  bool loadStarted = false;

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

Here too.

 
   String get hoverText {
     if (ref == null) {
       return super.hoverText;
     }
-    if (line < 0) {
-      return ref.vmName;
-    } else {
-      return '${ref.vmName}:$line';
+    return ref.vmName;
+  }
+
+  void posChanged(oldValue) {
+    loadStarted = false;
+    _updateProperties();
+  }
+
+  void _updateProperties(_) {
+    if (ref.loaded) {
+      notifyPropertyChange(#name, 0, 1);
+      notifyPropertyChange(#url, 0, 1);
     }
   }
 
   String get name {
     if (ref == null) {
       return super.name;
     }
-    if (line < 0) {
-      return ref.name;
-    } else {
-      return '${ref.name}:$line';
+    if (pos >= 0) {
+      if (ref.loaded) {
+        // Script is loaded, get the line number.
+        Script script = ref;
+        return '${super.name}:${script.tokenToLine(pos)}';
+      } else if (!loadStarted) {
+        // Script is not loaded.  Load now.
+        loadStarted = true;
+        ref.load().then(_updateProperties);
+      }
     }
+    return super.name;
+  }
+
+  String get url {
+    if (ref == null) {
+      return super.url;
+    }
+    if (pos >= 0) {
+      if (ref.loaded) {
+        // Script is loaded, get the line number.
+        Script script = ref;
+        return '${super.url}#line=${script.tokenToLine(pos)}';
+      } else if (!loadStarted) {
+        // Script is not loaded.  Load now.
+        loadStarted = true;
+        ref.load().then(_updateProperties);
+      }
+    }
+    return super.url;
   }
 
   ScriptRefElement.created() : super.created();
 }