Add public_config to :libdart in runtime/BUILD.gn

runtime/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # TODO(zra): These build arguments should likely be moved to a gni file that is
 # included in BUILD.gn files that care about the values of the flags. For now,
 # since the GN build only happens as part of a Mojo build there is no need for
 # the indirection.
 declare_args() {
   # Instead of using is_debug, we introduce a different flag for specifying a
   # Debug build of Dart so that clients can still use a Release build of Dart
   # while themselves doing a Debug build.
   dart_debug = false
 }
 
+config("dart_public_config") {
+  include_dirs = [
+    ".",
+  ]
+}
+
 config("dart_config") {
   defines = []
   if (dart_debug) {
     defines += ["DEBUG"]
   } else {
     defines += ["NDEBUG"]
   }
 
   cflags = [
     "-Werror",
@@ skipping 33 matching lines @@
   configs += [":dart_config"]
   deps = [
     "vm:libdart_lib",
     "vm:libdart_vm",
     "third_party/double-conversion/src:libdouble_conversion",
     ":generate_version_cc_file",
   ]
   include_dirs = [
     ".",
   ]
+  public_configs = [":dart_public_config"]
   sources = [
     "include/dart_api.h",
     "include/dart_mirrors_api.h",
     "include/dart_native_api.h",
     "include/dart_tools_api.h",
     "vm/dart_api_impl.cc",
     "vm/debugger_api_impl.cc",
     "vm/mirrors_api_impl.cc",
     "vm/native_api_impl.cc",
     "vm/version.h",
@@ skipping 35 matching lines @@
     "vm:libdart_lib_nosnapshot",
     "vm:libdart_lib",
     "vm:libdart_vm",
     "vm:libdart_platform",
     "third_party/double-conversion/src:libdouble_conversion",
   ]
   sources = [
     "vm/libdart_dependency_helper.cc",
   ]
 }