[webkit-changes] [WebKit/WebKit] 55a286: REGRESSION (STP): Video won't play on bilibili.com

[Jean-Yves Avenard]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 55a286438b239e94c5a355a1f7510cfa7b4dd033
      https://github.com/WebKit/WebKit/commit/55a286438b239e94c5a355a1f7510cfa7b4dd033
  Author: Jean-Yves Avenard <jya at apple.com>
  Date:   2023-10-18 (Wed, 18 Oct 2023)

  Changed paths:
    M LayoutTests/fast/dom/document-contentType-DOMParser-expected.txt
    M LayoutTests/fast/dom/document-contentType-DOMParser.html
    M Source/WebCore/html/parser/HTMLDocumentParserFastPath.cpp
    M Source/WebCore/html/parser/HTMLDocumentParserFastPath.h
    M Source/WebCore/xml/DOMParser.cpp

  Log Message:
  -----------
  REGRESSION (STP): Video won't play on bilibili.com
https://bugs.webkit.org/show_bug.cgi?id=263196
rdar://117020123

Reviewed by Chris Dumez.

bilibili injects DOM objects in the tree by calling:
```
var t = (new DOMParser).parseFromString(e, "text/html");
return document.adoptNode(t.body.firstChild)
```

Per spec, when parsing HTML to create a document through DOMParser::parseFromString() [1]
you are to skip the whitespace tokens for the "initial" insertion mode [2].
The trailing spaces however must be kept [3]
This behaviour was regressed by 267202 at main.

On this site, the observable behaviour was that the firstChild became a "#text"
node rather the expected first DIV one.

So we trim the leading whitespaces before calling the fast parser. Which
restore the original behaviour prior 267202 at main

[1] https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#parse-html-from-a-string
[2] https://html.spec.whatwg.org/multipage/parsing.html#the-initial-insertion-mode
[3] https://html.spec.whatwg.org/multipage/parsing.html#parsing-main-afterbody

* LayoutTests/fast/dom/document-contentType-DOMParser-expected.txt:
* LayoutTests/fast/dom/document-contentType-DOMParser.html: Added tests.
* Source/WebCore/html/parser/HTMLDocumentParserFastPath.cpp:
(WebCore::tryFastParsingHTMLFragment):
* Source/WebCore/html/parser/HTMLDocumentParserFastPath.h: Change type to StringView
(WebCore::requires):
* Source/WebCore/xml/DOMParser.cpp:
(WebCore::DOMParser::parseFromString):

Canonical link: https://commits.webkit.org/269457@main