This reverts commit crrev.com/4e9b50ab
and thus relands the following commits:

  ebdd0db4: "gclient: Remove URLs from hierarchy."
  54a5c2ba: "gclient: Refactor PrintRevInfo"
  083eb25f: "gclient: Don't allow URL to be None."

When a None URL is specified in a .gclient file, and a DEPS file is
given, the DEPS file is treated as a .gclient file and its dependencies
are added.

Bug: 839925

Change-Id: I1068b66487874bfa0a788bf9da5273714b6ad39e
Reviewed-on: https://chromium-review.googlesource.com/1083340
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Aaron Gable <agable@chromium.org>
Reviewed-by: Michael Moss <mmoss@chromium.org>