Bug 1804406 - Prevent internal SVG elements from becoming query containers for size features. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D164045

layout/style/nsStyleStruct.cpp

@@ -3729,6 +3729,13 @@ ContainSizeAxes nsStyleDisplay::GetContainSizeAxes(
     return ContainSizeAxes(false, false);
   }
 
+  // Internal SVG elements do not use the standard CSS box model, and wouldn't
+  // be affected by size containment. By disabling it we prevent them from
+  // becoming query containers for size features.
+  if (aFrame.HasAnyStateBits(NS_FRAME_SVG_LAYOUT)) {
+    return ContainSizeAxes(false, false);
+  }
+
   // https://drafts.csswg.org/css-contain-2/#content-visibility
   // If this content skips its content via content-visibility, it always has
   // size containment.

testing/web-platform/meta/css/css-contain/container-queries/never-match-container.html.ini

@@ -1,3 +0,0 @@
-[never-match-container.html]
-  [Size @container query against svg element never matches]
-    expected: FAIL

testing/web-platform/meta/css/css-contain/container-queries/svg-foreignobject-no-size-container.html.ini

@@ -1,4 +0,0 @@
-[svg-foreignobject-no-size-container.html]
-  expected:
-    if (os == "android") and not debug: TIMEOUT
-    FAIL