Fix an analyzer error in http and barback.

R=rnystrom@google.com
BUG=

Review URL: https://codereview.chromium.org//62443006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/http@30331 260f80e4-7a28-3924-810f-c04153c831b5
1 file changed
tree: 3207ac83eaf9e49516f07d4ce753ee7a6f193829
  1. lib/
  2. test/
  3. pubspec.yaml