fix csslib and watcher warnings
fix csslib and watcher warnings

R=rnystrom@google.com, terry@google.com

Review URL: https://codereview.chromium.org//50703011

git-svn-id: c53bd6455474c0a826d309663cf600546f7b0963@29632 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/watcher