Support loading binary data in dart2js

tests/compiler/dart2js/library_resolution_test.dart

Index: tests/compiler/dart2js/library_resolution_test.dart
diff --git a/tests/compiler/dart2js/library_resolution_test.dart b/tests/compiler/dart2js/library_resolution_test.dart
index cbbd114cd65c12e21f2c51071e55506a73a50bdb..c0c97832a02e0e193a20909324475540c22bdbd6 100644
--- a/tests/compiler/dart2js/library_resolution_test.dart
+++ b/tests/compiler/dart2js/library_resolution_test.dart
@@ -16,11 +16,11 @@ import "package:async_helper/async_helper.dart";
 
 import 'package:expect/expect.dart' show Expect;
 
+import 'package:compiler/compiler_new.dart';
+
 import 'package:compiler/src/diagnostics/messages.dart'
     show MessageKind, MessageTemplate;
 
-import 'package:compiler/src/elements/elements.dart' show LibraryElement;
-
 import 'package:compiler/src/library_loader.dart' show LoadedLibraries;
 
 import 'package:compiler/src/null_compiler_output.dart' show NullCompilerOutput;
@@ -49,14 +49,18 @@ main() async {
   var provider = new MemorySourceFileProvider(MEMORY_SOURCE_FILES);
   var handler = new FormattingDiagnosticHandler(provider);
 
-  Future wrappedProvider(Uri uri) {
+  Future wrappedProvider(Uri uri) async {
     if (uri == mock1LibraryUri) {
-      return provider.readUtf8BytesFromUri(Uri.parse('memory:mock1.dart'));
+      return (await provider.readBytesFromUri(

[Siggi Cherem (dart-lang), 2017/05/22 22:21:36]

nit, how about just updating 'uri' instead and calling readBytes once below?

if (uri == mockLibraryUri) {
  uri = Uri.parse('memory:mock1.dart');
} else if (uri == mock2LibraryUri) {
  uri = Uri.parse('memory:mock2.dart');
}
Input input = await provider.readBtesFromUri(uri, InputKind.utf8);
return input.data;

[Johnni Winther, 2017/05/23 08:43:15]

Done.

+              Uri.parse('memory:mock1.dart'), InputKind.utf8))
+          .data;
     }
     if (uri == mock2LibraryUri) {
-      return provider.readUtf8BytesFromUri(Uri.parse('memory:mock2.dart'));
+      return (await provider.readBytesFromUri(
+              Uri.parse('memory:mock2.dart'), InputKind.utf8))
+          .data;
     }
-    return provider.readUtf8BytesFromUri(uri);
+    return (await provider.readBytesFromUri(uri, InputKind.utf8)).data;
   }
 
   String expectedMessage = MessageTemplate