Revert of Move GN grit scripts out of secondary tree.

tools/grit/repack.gni

-# Copyright 2014 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-# This file defines a template to invoke grit repack in a consistent manner.
-#
-# Parameters:
-#   sources  [required]
-#       List of pak files that need to be combined.
-#
-#   output  [required]
-#       File name (single string) of the output file.
-#
-#   repack_options  [optional]
-#       List of extra arguments to pass.
-#
-#   deps  [optional]
-#   visibility  [optional]
-#       Normal meaning.
-template("repack") {
-  action(target_name) {
-    assert(defined(invoker.sources), "Need sources for $target_name")
-    assert(defined(invoker.output), "Need output for $target_name")
-
-    if (defined(invoker.visibility)) {
-      visibility = invoker.visibility
-    }
-
-    script = "//tools/grit/grit/format/repack.py"
-
-    inputs = invoker.sources
-    outputs = [
-      invoker.output,
-    ]
-
-    args = []
-    if (defined(invoker.repack_options)) {
-      args += invoker.repack_options
-    }
-    args += [ rebase_path(invoker.output, root_build_dir) ]
-    args += rebase_path(invoker.sources, root_build_dir)
-
-    if (defined(invoker.deps)) {
-      deps = invoker.deps
-    }
-  }
-}