Scanner can include comments in the token stream.

lib/compiler/implementation/scanner/array_based_scanner.dart

Index: lib/compiler/implementation/scanner/array_based_scanner.dart
diff --git a/lib/compiler/implementation/scanner/array_based_scanner.dart b/lib/compiler/implementation/scanner/array_based_scanner.dart
index 5e15bb5673497d3282e8f97428967eef5a92cd6a..aa05ea83fd159458630759aeb30dc08245f02cea 100644
--- a/lib/compiler/implementation/scanner/array_based_scanner.dart
+++ b/lib/compiler/implementation/scanner/array_based_scanner.dart
@@ -8,13 +8,14 @@ class ArrayBasedScanner<S extends SourceString> extends AbstractScanner<S> {
   Token tail;
   int tokenStart;
   int byteOffset;
+  final bool includeComments;
 
   /** Since the input is UTF8, some characters are represented by more
    * than one byte. [extraCharOffset] tracks the difference. */
   int extraCharOffset;
   Link<BeginGroupToken> groupingStack = const EmptyLink<BeginGroupToken>();
 
-  ArrayBasedScanner()
+  ArrayBasedScanner(this.includeComments)
     : this.extraCharOffset = 0,
       this.tokenStart = -1,
       this.byteOffset = -1,
@@ -164,6 +165,12 @@ class ArrayBasedScanner<S extends SourceString> extends AbstractScanner<S> {
     }
   }
 
+  void appendComment() {
+    if (!includeComments) return;
+    SourceString value = utf8String(tokenStart, -1);
+    appendByteStringToken(COMMENT_INFO, value);
+  }
+
   void discardOpenLt() {
     while (!groupingStack.isEmpty() && groupingStack.head.kind === LT_TOKEN) {
       groupingStack = groupingStack.tail;