Start preparing tests to accept binary compiler input.

tests/compiler/dart2js/memory_source_file_helper.dart

Index: tests/compiler/dart2js/memory_source_file_helper.dart
diff --git a/tests/compiler/dart2js/memory_source_file_helper.dart b/tests/compiler/dart2js/memory_source_file_helper.dart
index a198aefdbd1e556177b006c65d58b02f760d7b47..53521cdda4fda7ced7d9b842f121380416b3a72e 100644
--- a/tests/compiler/dart2js/memory_source_file_helper.dart
+++ b/tests/compiler/dart2js/memory_source_file_helper.dart
@@ -12,7 +12,7 @@ export 'package:compiler/src/apiimpl.dart' show CompilerImpl;
 export 'package:compiler/src/filenames.dart' show currentDirectory;
 
 import 'package:compiler/src/io/source_file.dart'
-    show StringSourceFile, SourceFile;
+    show StringSourceFile, SourceFile, Utf8BytesSourceFile;
 
 import 'package:compiler/src/source_file_provider.dart' show SourceFileProvider;
 
@@ -20,38 +20,48 @@ export 'package:compiler/src/source_file_provider.dart'
     show SourceFileProvider, FormattingDiagnosticHandler;
 
 class MemorySourceFileProvider extends SourceFileProvider {
-  Map<String, String> memorySourceFiles;
+  Map<String, dynamic> memorySourceFiles;
 
-  MemorySourceFileProvider(Map<String, String> this.memorySourceFiles);
+  /// MemorySourceFiles can contain maps of file names to string contents or
+  /// file names to binary contents.
+  MemorySourceFileProvider(Map<String, dynamic> this.memorySourceFiles);
 
-  Future<String> readStringFromUri(Uri resourceUri) {
+  Future<List<int>> readUtf8BytesFromUri(Uri resourceUri) {
     if (resourceUri.scheme != 'memory') {
-      return super.readStringFromUri(resourceUri);
+      return super.readUtf8BytesFromUri(resourceUri);
     }
-    String source = memorySourceFiles[resourceUri.path];
+    var source = memorySourceFiles[resourceUri.path];
     if (source == null) {
       return new Future.error(new Exception(
           'No such memory file $resourceUri in ${memorySourceFiles.keys}'));
     }
-    this.sourceFiles[resourceUri] =
-        new StringSourceFile.fromUri(resourceUri, source);
+    var sourceFile;
+    if (source is String) {
+      sourceFile = new StringSourceFile.fromUri(resourceUri, source);
+    } else {
+      sourceFile = new Utf8BytesSourceFile(resourceUri, source);
+    }
+    this.sourceFiles[resourceUri] = sourceFile;
     return new Future.value(source);
   }
 
-  Future<String> call(Uri resourceUri) => readStringFromUri(resourceUri);
+  Future<List<int>> call(Uri resourceUri) => readUtf8BytesFromUri(resourceUri);
 
   SourceFile getSourceFile(Uri resourceUri) {
     if (resourceUri.scheme != 'memory') {
       return super.getSourceFile(resourceUri);
     }
-    String source = memorySourceFiles[resourceUri.path];
+    var source = memorySourceFiles[resourceUri.path];
     if (source == null) {
       throw new Exception(
           'No such memory file $resourceUri in ${memorySourceFiles.keys}');
     }
-    return new StringSourceFile.fromUri(resourceUri, source);
+    if (source is String) {
+      return new StringSourceFile.fromUri(resourceUri, source);
+    }
+    return new Utf8BytesSourceFile(resourceUri, source);
   }
 
   @override
-  Future readFromUri(Uri resourceUri) => readStringFromUri(resourceUri);
+  Future readFromUri(Uri resourceUri) => readUtf8BytesFromUri(resourceUri);
 }