[infra] Translate _sources.gypi files to _sources.gni files

sdk/lib/core/core_sources.gni

Index: sdk/lib/core/core_sources.gni
diff --git a/sdk/lib/core/core_sources.gni b/sdk/lib/core/core_sources.gni
new file mode 100644
index 0000000000000000000000000000000000000000..ad8e40dd967661c459331f24a40bfa0aa3801ecc
--- /dev/null
+++ b/sdk/lib/core/core_sources.gni
@@ -0,0 +1,42 @@
+# Copyright (c) 2017, 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.
+
+core_sdk_sources = [
+  "core.dart",
+
+  # The above file needs to be first as it lists the parts below.
+  "annotations.dart",
+  "bool.dart",
+  "comparable.dart",
+  "date_time.dart",
+  "double.dart",
+  "duration.dart",
+  "errors.dart",
+  "exceptions.dart",
+  "expando.dart",
+  "function.dart",
+  "identical.dart",
+  "int.dart",
+  "invocation.dart",
+  "iterable.dart",
+  "iterator.dart",
+  "list.dart",
+  "map.dart",
+  "null.dart",
+  "num.dart",
+  "object.dart",
+  "pattern.dart",
+  "print.dart",
+  "regexp.dart",
+  "set.dart",
+  "sink.dart",
+  "stacktrace.dart",
+  "stopwatch.dart",
+  "string.dart",
+  "string_buffer.dart",
+  "string_sink.dart",
+  "symbol.dart",
+  "type.dart",
+  "uri.dart",
+]