[WEB-16445] When create a missing imported library/part, add the edit once.

R=brianwilkerson@google.com
BUG= https://youtrack.jetbrains.com/issue/WEB-16445

Review URL: https://codereview.chromium.org//1147543002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@45813 260f80e4-7a28-3924-810f-c04153c831b5
2 files changed
tree: 512bd3d2535b13c853ef495b7add983699017006
  1. dart/
  2. deps/