Roll dart to 48a927acb2dc4178691b4ddfa817e87043e30b01 (#4409)

* Roll dart to f5fc335a4cdfcf96ae550044c64044ffe599e595

* Update license hash

* Roll a little further to pick up a revert

* Update hash

DEPS

@@ -31,7 +31,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': 'edf890f30cb465f508933d065a60147f1cd3e038',
+  'dart_revision': '48a927acb2dc4178691b4ddfa817e87043e30b01',
 
   'dart_args_tag': '0.13.7',
   'dart_async_tag': '2.0.0',

frontend_server/lib/server.dart

@@ -5,12 +5,18 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
-import 'package:front_end/compilation_message.dart';
 
-import 'package:front_end/byte_store.dart';
-import 'package:front_end/compiler_options.dart';
-import 'package:front_end/incremental_kernel_generator.dart';
-import 'package:front_end/kernel_generator.dart';
+// front_end/src imports below that require lint `ignore_for_file`
+// are a temporary state of things until frontend team builds better api
+// that would replace api used below. This api was made private in
+// an effort to discourage further use.
+// ignore_for_file: implementation_imports
+import 'package:front_end/src/api_prototype/compilation_message.dart';
+
+import 'package:front_end/src/api_prototype/byte_store.dart';
+import 'package:front_end/src/api_prototype/compiler_options.dart';
+import 'package:front_end/src/api_prototype/incremental_kernel_generator.dart';
+import 'package:front_end/src/api_prototype/kernel_generator.dart';
 import 'package:kernel/ast.dart';
 import 'package:kernel/binary/ast_to_binary.dart';
 import 'package:kernel/binary/limited_ast_to_binary.dart';

frontend_server/test/server_test.dart

@@ -5,7 +5,12 @@ import 'dart:isolate';
 
 import 'package:args/src/arg_results.dart';
 import 'package:frontend_server/server.dart';
-import 'package:front_end/incremental_kernel_generator.dart';
+// front_end/src imports below that require lint `ignore_for_file`
+// are a temporary state of things until frontend team builds better api
+// that would replace api used below. This api was made private in
+// an effort to discourage further use.
+// ignore_for_file: implementation_imports
+import 'package:front_end/src/api_prototype/incremental_kernel_generator.dart';
 import 'package:kernel/binary/ast_to_binary.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';

travis/licenses_golden/licenses_third_party

-Signature: a649965ef4df4827f2d3717dd9cbfa5e
+Signature: 10482740f1ff7f7f20959cd3d98e9ff5
 
 UNUSED LICENSES: