[flutter_localizations] Add BUILD.gn for flutter_localizations (#26440)

packages/flutter_localizations/BUILD.gn

@@ -0,0 +1,19 @@
+# Copyright 2019 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_localizations") {
+  package_name = "flutter_localizations"
+
+  # Can be left empty as analysis is disabled.
+  sources = []
+
+  disable_analysis = true
+
+  deps = [
+    "../flutter",
+    "//third_party/dart/third_party/pkg/intl",
+  ]
+}