[Fasta] include source code in dill

pkg/kernel/lib/binary/ast_from_binary.dart

Index: pkg/kernel/lib/binary/ast_from_binary.dart
diff --git a/pkg/kernel/lib/binary/ast_from_binary.dart b/pkg/kernel/lib/binary/ast_from_binary.dart
index a4d4a941efecb06d591a67e197507975cf2e9fc3..aa9641b672f5901a4a675b1089cd4fb6f5e31dbc 100644
--- a/pkg/kernel/lib/binary/ast_from_binary.dart
+++ b/pkg/kernel/lib/binary/ast_from_binary.dart
@@ -4,6 +4,7 @@
 library kernel.ast_from_binary;
 
 import 'dart:convert';
+import 'dart:typed_data';
 
 import '../ast.dart';
 import '../transformations/flags.dart';
@@ -74,6 +75,13 @@ class BinaryBuilder {
         readByte();
   }
 
+  List<int> readUtf8Bytes() {
+    List<int> bytes = new Uint8List(readUInt());
+    bytes.setRange(0, bytes.length, _bytes, _byteIndex);
+    _byteIndex += bytes.length;
+    return bytes;
+  }
+
   String readStringEntry() {
     int numBytes = readUInt();
     // Utf8Decoder will skip leading BOM characters, but we must preserve them.
@@ -271,7 +279,7 @@ class BinaryBuilder {
     Map<String, Source> uriToSource = <String, Source>{};
     for (int i = 0; i < length; ++i) {
       String uri = _sourceUriTable[i];
-      String sourceCode = readStringEntry();
+      List<int> sourceCode = readUtf8Bytes();
       int lineCount = readUInt();
       List<int> lineStarts = new List<int>(lineCount);
       int previousLineStart = 0;