GN: asset_location -> android_assets() for mandoline_apk

mojo/generate_mojo_shell_assets_list.gni

-# 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.
-
-# Used to generate an assets_list file. To use supply the argument 'dir', which
-# is where the assets can be found.
-# TODO(sky): Perhaps combine this with the copy step?
-template("generate_mojo_shell_assets_list") {
-  action(target_name) {
-    script = "//mojo/tools/generate_mojo_shell_assets_list.py"
-    args = [
-      "--dir",
-      rebase_path(invoker.dir, root_build_dir),
-    ]
-    outputs = [
-      invoker.dir + "/assets_list",
-    ]
-    if (defined(invoker.deps)) {
-      deps = invoker.deps
-    }
-    if (defined(invoker.testonly)) {
-      testonly = invoker.testonly
-    }
-  }
-}