Fix a bad merge in pkg/stack_trace. TBR R=rnystrom@google.com Review URL: https://codereview.chromium.org//22880030 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/stack_trace@26467 260f80e4-7a28-3924-810f-c04153c831b5