What's new in the WebKitGTK 2.53.4 release?
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  - Implemented batched painting in skia compositor, which improves performance when
    there are many layers that can be painted in the same operation.
  - Avoid unnecessary clips when possible in skia compositor.
  - Fix synchronization issues between main, scrolling and compositing threads causing
    glitches while scrolling in some cases.
  - Limit the damage region of the scrollbar to the region actually painted.
  - Add support for image/webp to canvas.toDataURL().
  - Expose search inputs as WEBKIT_INPUT_PURPOSE_SEARCH.
  - Add User-Agent quirk for HBO Max.
  - Fix several crashes and rendering issues.