dart2js call stacks too hard to understand

[rakudrama]

Breaking into the Clock sample running on Chrome, the stack trace is of almost no use.

Developers will have to debug code on Chrome, Safari, IE, Opera and whatever else. Basic information needs to be in the JS stacktrace.
dart2js+Chrome: No class names appear in the stack trace at all.

dart2js stack:

Isolate.$defineClass.newDistanceSquared$3 (Clock.dart.js:768)
Isolate.$defineClass.$call$1 (Clock.dart.js:1134)
$.forEach2 (Clock.dart.js:2280)
$.forEach (Clock.dart.js:2250)
Isolate.$defineClass.$call$1 (Clock.dart.js:1124)
$.forEach2 (Clock.dart.js:2280)
$.forEach (Clock.dart.js:2250)
Isolate.$defineClass.collideBalls$1 (Clock.dart.js:779)
Isolate.$defineClass.tick$0 (Clock.dart.js:787)
Isolate.$defineClass.$call$0 (Clock.dart.js:1053)
Isolate.$defineClass.$call$0 (Clock.dart.js:1158)
$.invokeClosure (Clock.dart.js:1656)
function0 (Clock.dart.js:1478)

dart2js code:
Isolate.$defineClass("Balls", "Object", ["balls?", "lastTime", "root?"], {
 ...
 newDistanceSquared$3: function(delta, b0, b1) {
[*] var nb0x = $.add(b0.get$x(), $.mul(b0.get$vx(), delta));
  var nb0y = $.add(b0.get$y(), $.mul(b0.get$vy(), delta));
  var nb1x = $.add(b1.get$x(), $.mul(b1.get$vx(), delta));
  var nb1y = $.add(b1.get$y(), $.mul(b1.get$vy(), delta));
  var ndx = $.abs($.sub(nb0x, nb1x));
  var ndy = $.abs($.sub(nb0y, nb1y));
  return $.add($.mul(ndx, ndx), $.mul(ndy, ndy));
 },

Frog is somewhat better, but still inadequate.
At least it is not substantially worse than debugging in JavaScript using Closure.
Example: class name 'Balls' appears:

frog stack:
Balls.newDistanceSquared (Clock.dart.js_:3117)
(anonymous function) (Clock.dart.js_:3094)
ListIterator.hasNext (Clock.dart.js_:545)
(anonymous function) (Clock.dart.js_:3089)
ListIterator.hasNext (Clock.dart.js_:545)
Balls.collideBalls (Clock.dart.js_:3088)
Balls.tick (Clock.dart.js_:3084)
f (Clock.dart.js_:2971)

frog code at breakpoint:

Balls.prototype.newDistanceSquared = function(delta, b0, b1) {
[*] var nb0x = b0.x + b0.vx * delta;
  var nb0y = b0.y + b0.vy * delta;
  var nb1x = b1.x + b1.vx * delta;
  var nb1y = b1.y + b1.vy * delta;
  var ndx = (nb0x - nb1x).abs();
  var ndy = (nb0y - nb1y).abs();
  var nd2 = ndx * ndx + ndy * ndy;
  return nd2;
}

[kasperl]

Set owner to @floitschG.
Added Accepted label.

[floitschG]

This should be fixed with r8460.

---

Added Fixed label.