This DEPS file specifies the extra dependencies required to build
Chromium for Chromium OS.  It lives here in src/tools/cros.DEPS, but
is generally checked out to another location by a custom rule in your
.gclient file, often a cros_deps/ directory next to your src/
directory.  For example:

  { "name"        : "cros_deps",
    "url"         : "http://src.chromium.org/svn/trunk/src/tools/cros.DEPS"
  },

If you want to rev these deps and publish them for all to see,
edit src/tools/cros.DEPS/DEPS.  If you want to rev the deps locally first,
edit the file in the location to which your .gclient file checks it out
(in most cases, cros_deps/DEPS), but note that you cannot push a modification
from there.