Create common script file for workon tools. Planning on using in another CL.

lib/cros_workon_common.sh

+#!/bin/bash
+
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Common library for functions used by workon tools.
+
+show_workon_ebuilds() {
+  pushd "${BOARD_DIR}"/etc/ 1> /dev/null
+  source make.conf
+  popd 1> /dev/null
+  local CROS_OVERLAYS="${PORTDIR_OVERLAY}"
+
+  for overlay in ${CROS_OVERLAYS}; do
+    pushd ${overlay} 1> /dev/null
+    find . -name '*.ebuild' | xargs fgrep cros-workon | \
+      awk -F / '{ print $2 "/" $3 }' | uniq | sort
+    popd 1> /dev/null
+  done
+}