Make all DDC internal stack traces apply source maps.

pkg/dev_compiler/tool/input_sdk/private/js_helper.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 dart._js_helper;
 
 import 'dart:collection';
 
+import 'dart:_debugger' show stackTraceMapper;
+
 import 'dart:_foreign_helper' show
     JS,
     JS_STRING_CONCAT;
 
 import 'dart:_interceptors';
 import 'dart:_internal' show
     EfficientLengthIterable,
     MappedIterable,
     IterableElementError;
 
@@ skipping 602 matching lines @@
 
 /**
  * Called by generated code to fetch the stack trace from an
  * exception. Should never return null.
  */
 StackTrace getTraceFromException(exception) => new _StackTrace(exception);
 
 class _StackTrace implements StackTrace {
   var _exception;
   String _trace;
+
   _StackTrace(this._exception);
 
   String toString() {
-    if (_trace != null) return JS('String', '#', _trace);
+    if (_trace != null) return _trace;
 
     String trace;
     if (JS('bool', '# !== null', _exception) &&
         JS('bool', 'typeof # === "object"', _exception)) {
       trace = JS("String|Null", r"#.stack", _exception);
+      if (trace != null && stackTraceMapper != null) {
+        trace = stackTraceMapper(trace);
+      }
     }
     return _trace = (trace == null) ? '' : trace;
   }
 }
 
 int objectHashCode(var object) {
   if (object == null || JS('bool', "typeof # != 'object'", object)) {
     return object.hashCode;
   } else {
     return Primitives.objectHashCode(object);
@@ skipping 257 matching lines @@
   // we have no way of telling the compiler yet, so it will generate an extra
   // layer of indirection that wraps the SyncIterator.
   _jsIterator() => JS('', '#(...#)', _generator, _args);
 
   Iterator<E> get iterator => new SyncIterator<E>(_jsIterator());
 }
 
 class BooleanConversionAssertionError extends AssertionError {
   toString() => 'Failed assertion: boolean expression must not be null';
 }