GN: Add support for prebuilt instrumented libraries.

third_party/instrumented_libraries/scripts/unpack_binaries.sh

Index: third_party/instrumented_libraries/scripts/unpack_binaries.sh
diff --git a/third_party/instrumented_libraries/scripts/unpack_binaries.sh b/third_party/instrumented_libraries/scripts/unpack_binaries.sh
deleted file mode 100755
index 12af6adc578208026f640095ac895539497498c5..0000000000000000000000000000000000000000
--- a/third_party/instrumented_libraries/scripts/unpack_binaries.sh
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/bin/bash
-# Copyright 2015 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.
-
-# Unpacks an archive containing prebuilt instrumented libraries into output dir.
-
-archive_file=$1
-target_dir=$2
-stamp_file=$3
-
-rm ${target_dir}/* -rf
-tar -zxf ${archive_file} -C ${target_dir}
-
-touch ${stamp_file}