Bug 226521

Summary:	[WPE] imported/w3c/web-platform-tests/html/semantics/embedded-content/the-img-element/source-media-outside-doc.html is flaky failing since added in 237111@main
Product:	WebKit	Reporter:	Lauro Moura <lmoura>
Component:	WPE WebKit	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	bugs-noreply, calvaris
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Lauro Moura 2021-06-01 22:17:11 PDT

imported/w3c/web-platform-tests/html/semantics/embedded-content/the-img-element/source-media-outside-doc.html

Flaky failing in Release bot only. Testing locally, always fails.

Flaky failure on both cases:

--- /home/lauro/dev/WebKit/layout-test-results/imported/w3c/web-platform-tests/html/semantics/embedded-content/the-img-element/source-media-outside-doc-expected.txt
+++ /home/lauro/dev/WebKit/layout-test-results/imported/w3c/web-platform-tests/html/semantics/embedded-content/the-img-element/source-media-outside-doc-actual.txt
@@ -1,4 +1,4 @@
 
 
-PASS Image source selection using media queries is performed for img elements outside the document
+FAIL Image source selection using media queries is performed for img elements outside the document assert_equals: Initial currentSrc value expected "data:,a" but got "data:,c"
 

In GTK it's working fine. No change in behavior regardless of headless/weston/wayland drivers.

Looks like somehow in WPE Release the media query is failing for the source elements (evaluation fails in HTMLImageElement::bestFitSourceFromPictureElement()), making it rely on the img element's own src atribute.