Introduce "platform configurations" to replace categories and libraries.dart.

sdk/lib/dart_server.platform

Index: sdk/lib/dart_server.platform
diff --git a/sdk/lib/dart_server.platform b/sdk/lib/dart_server.platform
new file mode 100644
index 0000000000000000000000000000000000000000..bbb6e0f46ad1acc95fff6f14045981d17a3029cc
--- /dev/null
+++ b/sdk/lib/dart_server.platform
@@ -0,0 +1,49 @@
+# Copyright (c) 2015, 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.
+
+# The platform for dart on the server with dart2js.
+#
+# Includes dart:io.
+# Does not include dart:html and associated libraries.
+
+[dart-spec]
+spec:3rd edition.
+
+[features]
+# No extra features.
+
+[libraries]
+async:async/async.dart
+collection:collection/collection.dart
+convert:convert/convert.dart
+core:core/core.dart
+developer:developer/developer.dart
+io:io/io.dart
+isolate:isolate/isolate.dart
+math:math/math.dart
+mirrors:mirrors/mirrors.dart
+nativewrappers:html/dart2js/nativewrappers.dart
+typed_data:typed_data/typed_data.dart
+_native_typed_data:_internal/js_runtime/lib/native_typed_data.dart
+html:unsupported:
+html_common:unsupported:
+indexed_db:unsupported:
+svg:unsupported:
+web_audio:unsupported:
+web_gl:unsupported:
+web_sql:unsupported:
+_chrome:unsupported:
+js:unsupported:
+_mirror_helper:unsupported:
+_internal:internal/internal.dart
+_js_helper:_internal/js_runtime/lib/js_helper.dart
+_interceptors:_internal/js_runtime/lib/interceptors.dart
+_foreign_helper:_internal/js_runtime/lib/foreign_helper.dart
+_isolate_helper:_internal/js_runtime/lib/isolate_helper.dart
+_js_mirrors:_internal/js_runtime/lib/js_mirrors.dart
+_js_names:_internal/js_runtime/lib/js_names.dart
+_js_primitives:_internal/js_runtime/lib/js_primitives.dart
+_js_embedded_names:_internal/js_runtime/lib/shared/embedded_names.dart
+_async_await_error_codes:_internal/js_runtime/lib/shared/async_await_error_codes.dart
+_metadata:html/html_common/metadata.dart