The Sky parser should yield before start tags

sky/engine/core/html/parser/BackgroundHTMLParser.cpp

 /*
  * Copyright (C) 2013 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 42 matching lines @@
 #endif
 
 base::WeakPtr<BackgroundHTMLParser> BackgroundHTMLParser::create(PassOwnPtr<BackgroundHTMLParser::Configuration> config)
 {
     // Caller must free by calling stop().
     BackgroundHTMLParser* parser = new BackgroundHTMLParser(config);
     return parser->m_weakFactory.GetWeakPtr();
 }
 
 BackgroundHTMLParser::BackgroundHTMLParser(PassOwnPtr<Configuration> config)
-    : m_token(adoptPtr(new HTMLToken))
+    : m_state(InitialState)
+    , m_token(adoptPtr(new HTMLToken))
     , m_tokenizer(HTMLTokenizer::create())
     , m_parser(config->parser)
     , m_pendingTokens(adoptPtr(new CompactHTMLTokenStream))
     , m_decoder(TextResourceDecoder::create())
     , m_source(config->source.Pass())
     , m_weakFactory(this)
 {
 }
 
 BackgroundHTMLParser::~BackgroundHTMLParser()
@@ skipping 35 matching lines @@
 {
     ASSERT(!m_input.isClosed());
     m_input.append(SegmentedString(String(&kEndOfFileMarker, 1)));
     m_input.close();
 }
 
 bool BackgroundHTMLParser::updateTokenizerState(const CompactHTMLToken& token)
 {
     if (token.type() == HTMLToken::StartTag) {
         const String& tagName = token.data();
+
         if (threadSafeMatch(tagName, HTMLNames::scriptTag) || threadSafeMatch(tagName, HTMLNames::styleTag))
             m_tokenizer->setState(HTMLTokenizer::RawDataState);
+
+        if (threadSafeMatch(tagName, HTMLNames::importTag)) {
+            m_state = DidSeeImportState;
+            return true;
+        }
+
+        if (m_state == InitialState)
+            return true;
+
+        m_state = InitialState;
+        return false;
     }
 
     return token.type() != HTMLToken::EndTag || !threadSafeMatch(token.data(), HTMLNames::scriptTag);
 }
 
 void BackgroundHTMLParser::pumpTokenizer()
 {
     while (true) {
         if (!m_tokenizer->nextToken(m_input, *m_token)) {
             // We've reached the end of our current input.
@@ skipping 24 matching lines @@
 
     OwnPtr<HTMLDocumentParser::ParsedChunk> chunk = adoptPtr(new HTMLDocumentParser::ParsedChunk);
     chunk->tokens = m_pendingTokens.release();
     Platform::current()->mainThreadTaskRunner()->PostTask(FROM_HERE,
         base::Bind(&HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser, m_parser, chunk.release()));
 
     m_pendingTokens = adoptPtr(new CompactHTMLTokenStream);
 }
 
 }