CSS stylesheets that error out block the parser and the load event

[jdm]

This is the cause of the 163.com testcase in tp5 failing to load. The early return in StylesheetContext::response_complete prevents us from removing the entry in the DocumentLoader's blocking loads list for a stylesheet that fails to load, and once that is corrected the parser refuses to unblock until the number of blocking stylesheets is also decreased. This diff makes the page load correctly for me.

@shinglyu, you may want to try running the full set with that diff applied and see how many other sites improve.

[shinglyu]

I run the patched version on TP5 and got the this:

========================================
Total 69 tests; 48 succeeded, 21 failed.

Failure summary:
 - http://localhost:8000/page_load_test/naver.com/www.naver.com/index.html
 - http://localhost:8000/page_load_test/noimpactman.typepad.com/noimpactman.typepad.com/index.html
 - http://localhost:8000/page_load_test/163.com/www.163.com/index.html
 - http://localhost:8000/page_load_test/thepiratebay.org/thepiratebay.org/top/201.html
 - http://localhost:8000/page_load_test/people.com.cn/people.com.cn/index.html
 - http://localhost:8000/page_load_test/reuters.com/www.reuters.com/index.html
 - http://localhost:8000/page_load_test/imdb.com/www.imdb.com/title/tt1099212/index.html
 - http://localhost:8000/page_load_test/homeway.com.cn/www.hexun.com/index.html
 - http://localhost:8000/page_load_test/indiatimes.com/www.indiatimes.com/index.html
 - http://localhost:8000/page_load_test/wsj.com/online.wsj.com/home-page.html
 - http://localhost:8000/page_load_test/slideshare.net/www.slideshare.net/jameswillamor/lolcats-in-popular-culture-a-historical-perspective.html
 - http://localhost:8000/page_load_test/chinaz.com/chinaz.com/index.html
 - http://localhost:8000/page_load_test/bild.de/www.bild.de/index.html
 - http://localhost:8000/page_load_test/xinhuanet.com/xinhuanet.com/index.html
 - http://localhost:8000/page_load_test/media.photobucket.com/media.photobucket.com/image/funny%20gif/findstuff22/Best%20Images/Funny/funny-gif1.jpg@o=1.html
 - http://localhost:8000/page_load_test/xunlei.com/xunlei.com/index.html
 - http://localhost:8000/page_load_test/store.apple.com/store.apple.com/us@mco=Nzc1MjMwNA.html
 - http://localhost:8000/page_load_test/digg.com/digg.com/news/story/New_logo_for_Mozilla_Firefox_browser.html
 - http://localhost:8000/page_load_test/mashable.com/mashable.com/index.html
 - http://localhost:8000/page_load_test/sohu.com/www.sohu.com/index.html
 - http://localhost:8000/page_load_test/ifeng.com/ifeng.com/index.html
========================================

(The total tests count is a little bit off, because I also counted sub pages e.g. iframes)

[shinglyu]

Comparing to #11087 , this fixed 3 pages, breaks 1 page (xunlei.com). photobucket failed, but this behavior started a few weeks ago, so it's not caused by your patch.

This is the diff

% diff -u old.txt new_sorted.txt                                                                                                                           1 ↵
--- old.txt 2016-06-02 13:55:07.692495607 +0800
+++ new_sorted.txt  2016-06-02 13:55:28.920567697 +0800
@@ -1,14 +1,13 @@
 http://localhost:8000/page_load_test/163.com/www.163.com/index.html
-http://localhost:8000/page_load_test/aljazeera.net/aljazeera.net/portal.html
 http://localhost:8000/page_load_test/bild.de/www.bild.de/index.html
 http://localhost:8000/page_load_test/chinaz.com/chinaz.com/index.html
 http://localhost:8000/page_load_test/digg.com/digg.com/news/story/New_logo_for_Mozilla_Firefox_browser.html
-http://localhost:8000/page_load_test/guardian.co.uk/www.guardian.co.uk/index.html
 http://localhost:8000/page_load_test/homeway.com.cn/www.hexun.com/index.html
 http://localhost:8000/page_load_test/ifeng.com/ifeng.com/index.html
 http://localhost:8000/page_load_test/imdb.com/www.imdb.com/title/tt1099212/index.html
 http://localhost:8000/page_load_test/indiatimes.com/www.indiatimes.com/index.html
 http://localhost:8000/page_load_test/mashable.com/mashable.com/index.html
+http://localhost:8000/page_load_test/media.photobucket.com/media.photobucket.com/image/funny%20gif/findstuff22/Best%20Images/Funny/funny-gif1.jpg@o=1.html
 http://localhost:8000/page_load_test/naver.com/www.naver.com/index.html
 http://localhost:8000/page_load_test/noimpactman.typepad.com/noimpactman.typepad.com/index.html
 http://localhost:8000/page_load_test/people.com.cn/people.com.cn/index.html
@@ -17,6 +16,6 @@
 http://localhost:8000/page_load_test/sohu.com/www.sohu.com/index.html
 http://localhost:8000/page_load_test/store.apple.com/store.apple.com/us@mco=Nzc1MjMwNA.html
 http://localhost:8000/page_load_test/thepiratebay.org/thepiratebay.org/top/201.html
-http://localhost:8000/page_load_test/uol.com.br/www.uol.com.br/index.html
 http://localhost:8000/page_load_test/wsj.com/online.wsj.com/home-page.html
 http://localhost:8000/page_load_test/xinhuanet.com/xinhuanet.com/index.html
+http://localhost:8000/page_load_test/xunlei.com/xunlei.com/index.html

[shinglyu]

@jdm I also noticed that when servo got stuck, the server log usually says it serving a gif file. We could probably check if gif loading or rendering is slow.

[jdm]

Huh, 163.com didn't finish loading? That's the one that I was testing.