Fix test to make sure that all opened file descriptors for a File have been closed before we attempt to delete it.
Fix test to make sure that all opened file descriptors for a File
have been closed before we attempt to delete it.

R=sgjesse@google.com
BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com//10270013

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@7158 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk