More header cleanup:

- Some cleanup to url_request.h
- Remove task.h from headers that don't need it.
- Remove histogram.h from message_loop.h

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/2986002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@52336 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 90242e9e03d4eeff67d9fbc97e555597206c69d1
6 files changed
tree: cb7af6d42af0707f9b7045369ffb434af71afdb6
  1. base/
  2. build/
  3. ipc/
  4. testing/