Parser: Make skipping HTML comments optional.

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index dbd8f1110108fdb17edd89958105f848e040e167..0d33aa0e340317889f5d111921d0ba9b274c16c5 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -58,6 +58,8 @@ class ParseInfo {
   FLAG_ACCESSOR(kAllowLazyParsing, allow_lazy_parsing, set_allow_lazy_parsing)
   FLAG_ACCESSOR(kAstValueFactoryOwned, ast_value_factory_owned,
                 set_ast_value_factory_owned)
+  FLAG_ACCESSOR(kIgnoreHtmlComments, ignore_html_comments,
+                set_ignore_html_comments)
 
 #undef FLAG_ACCESSOR
 
@@ -167,8 +169,9 @@ class ParseInfo {
     kParseRestriction = 1 << 6,
     kModule = 1 << 7,
     kAllowLazyParsing = 1 << 8,
+    kIgnoreHtmlComments = 1 << 9,
     // ---------- Output flags --------------------------
-    kAstValueFactoryOwned = 1 << 9
+    kAstValueFactoryOwned = 1 << 10
   };
 
   //------------- Inputs to parsing and scope analysis -----------------------