[gn] Add flutter_driver build file. (#17174)

packages/flutter_driver/BUILD.gn

+# Copyright 2018 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.
+
+import("//build/dart/dart_library.gni")
+
+dart_library("flutter_driver") {
+  package_name = "flutter_driver"
+
+  # Can be left empty as analysis is disabled.
+  sources = []
+
+  disable_analysis = true
+
+  deps = [
+    "//third_party/dart-pkg/git/flutter/packages/flutter",
+    "//third_party/dart-pkg/git/flutter/packages/flutter_test",
+    "//third_party/dart-pkg/pub/file",
+    "//third_party/dart-pkg/pub/json_rpc_2",
+    "//third_party/dart-pkg/pub/meta",
+    "//third_party/dart-pkg/pub/path",
+    "//third_party/dart-pkg/pub/web_socket_channel",
+    "//third_party/dart-pkg/pub/vm_service_client",
+  ]
+
+  if (is_fuchsia) {
+    deps += [ "$flutter_root/sky/packages/sky_engine:sky_engine_dart" ]
+  }
+}