Simplfy DEPS: always pull all deps, remove unused barelinux platform.

platform_tools/barelinux/bin/download_deps

-#!/bin/sh
-
-# Copyright 2014 Google Inc.
-#
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-# download_deps - download Skia's dependencies for a bare Linux system
-# (the normal dependecies plus giflib, libpng, and zlib.)
-
-try() {
-    # print an error on nonzero return code
-    "$@"
-    local ret=$?
-    if [ $ret != 0 ] ; then
-        echo "'$@' failed and returned ${ret}." >&2
-        return $ret
-    fi
-}
-
-try command -v gclient > /dev/null || exit
-cd "$(dirname "$0")/../../.."
-
-try gclient config --unmanaged --name . \
-    'https://skia.googlesource.com/skia.git' || exit
-
-echo 'target_os = ["barelinux"]' >> ./.gclient
-
-try gclient sync --jobs=1 || exit