[Webkit-unassigned] [Bug 212373] New: ResizeObserver doesn't trigger for elements with size in viewport values on window zoom

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=212373

            Bug ID: 212373
           Summary: ResizeObserver doesn't trigger for elements with size
                    in viewport values on window zoom
           Product: WebKit
           Version: Safari 13
          Hardware: Macintosh
                OS: macOS 10.15
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: New Bugs
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: neekitkah at gmail.com

1. Make a div with width in vw and height in vh
2. Create ResizeObserver and observe this div
3. Zoom browser window

Showcase: https://jsfiddle.net/yLdvctzx/14/show
Code: https://jsfiddle.net/yLdvctzx/14

Expected behavior:
ResizeObserver should detect resizing of the div and trigger its handler because elements's size in pixels has changed after zoom.

Actual behavior:
ResizeObserver doesn't trigger handler.
In the showcase example you can see that dimensions doesn't update on widnow resize.
Video demonstration: https://monosnap.com/file/WbacIuL2djfoCDiUE8Q5weaH1j1HEL

Chromium has the same issue (https://bugs.chromium.org/p/chromium/issues/detail?id=1086465). Works if FireFox.

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