03090df3fa
This moves the logic previously used in DDC for testing stepping via sourcemaps to a shared location so both DDC and dart2js can make use of the same thing. Bug: Change-Id: I83a2b1fc4fe5cefe3c8537e50d03c3e41e0490a8 Reviewed-on: https://dart-review.googlesource.com/24110 Commit-Queue: Jens Johansen <jensj@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>