Adding parse errors for tag name state

Author: Diego

lib/common/error_codes.js

@@ -7,6 +7,7 @@ module.exports = {
     endTagWithAttributes: 'end-tag-with-attributes',
     selfClosingEndTag: 'self-closing-end-tag',
     unexpectedNullCharacter: 'unexpected-null-character',
+    unexpectedEofCharacter: 'unexpected-eof-character',
     startOfProcessingInstructionOrXMLDeclaration: 'start-of-processing-instruction-or-xml-declaration',
     unexpectedFirstCharacterOfStartTagName: 'unexpected-first-character-of-start-tag-name',
     missingEndTagName: 'missing-end-tag-name',

lib/tokenizer/index.js

@@ -748,11 +748,15 @@ _[TAG_NAME_STATE] = function tagNameState(cp) {
     else if (isAsciiUpper(cp))
         this.currentToken.tagName += toAsciiLowerChar(cp);
 
-    else if (cp === $.NULL)
+    else if (cp === $.NULL) {
+        this._err(ERR.unexpectedNullCharacter);
         this.currentToken.tagName += UNICODE.REPLACEMENT_CHARACTER;
+    }
 
-    else if (cp === $.EOF)
+    else if (cp === $.EOF) {
+        this._err(ERR.unexpectedEofCharacter);
         this._emitEOFToken();
+    }
 
     else
         this.currentToken.tagName += toChar(cp);