Add Comment state errors.

Author: inikulin

lib/common/error_codes.js

@@ -16,5 +16,6 @@ module.exports = {
     malformedComment: 'malformed-comment',
     eofInScriptHtmlComment: 'eof-in-script-html-comment',
     nestedComment: 'nested-comment',
-    abruptComment: 'abrupt-comment'
+    abruptComment: 'abrupt-comment',
+    eofInComment: 'eof-in-comment'
 };

lib/tokenizer/index.js

@@ -1601,6 +1601,7 @@ _[COMMENT_START_DASH_STATE] = function commentStartDashState(cp) {
     }
 
     else if (cp === $.EOF) {
+        this._err(ERR.eofInComment);
         this._emitCurrentToken();
         this._emitEOFToken();
     }
@@ -1623,10 +1624,13 @@ _[COMMENT_STATE] = function commentState(cp) {
         this.state = COMMENT_LESS_THAN_SIGN_STATE;
     }
 
-    else if (cp === $.NULL)
+    else if (cp === $.NULL) {
+        this._err(ERR.unexpectedNullCharacter);
         this.currentToken.data += UNICODE.REPLACEMENT_CHARACTER;
+    }
 
     else if (cp === $.EOF) {
+        this._err(ERR.eofInComment);
         this._emitCurrentToken();
         this._emitEOFToken();
     }