Implementation of null-aware operators.

pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart

Index: pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
diff --git a/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart b/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
index d919596154580c9a6e09b6a710dfafb7142d9544..a8b27021e406748c145f3afa6e0bdddc7f600697 100644
--- a/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
+++ b/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
@@ -69,9 +69,10 @@ class Utf8BytesScanner extends ArrayBasedScanner {
    * array whose last element is '0' to signal the end of the file. If this
    * is not the case, the entire array is copied before scanning.
    */
-  Utf8BytesScanner(SourceFile file, {bool includeComments: false})
+  Utf8BytesScanner(SourceFile file, {bool includeComments: false,
+                                     bool enableNullAwareOperators: false})
       : bytes = file.slowUtf8ZeroTerminatedBytes(),
-        super(file, includeComments) {
+        super(file, includeComments, enableNullAwareOperators) {
     assert(bytes.last == 0);
     // Skip a leading BOM.
     if (_containsBomAt(0)) byteOffset += 3;