What's new in the WebKitGTK 2.51.3 release?
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  - Improve composition scheduling to avoid blocking waiting for tile painting.
  - Enable Pointer Events for touch input.
  - Building with Enchant 1.x is no longer supported, Enchant 2.x is now always
    used for spell checking.
  - Moved WebRTC network access to the NetworkProcess, when using GstWebRTC.
    This requires librice, and building with the CMake USE_LIBRICE option. When
    enabled, it is still possible to choose the older libnice-based implementation
    at runtime by setting WEBKIT_GST_DISABLE_WEBRTC_NETWORK_SANDBOX=1 in the
    environment.
  - Add support the XR_ANDROID_raycast OpenXR extension for WebXR Hit Testing.
  - Add support to use super-tiled graphics buffers when running on Vivante GPUs.
    Currently setting WEBKIT_SKIA_USE_VIVANTE_SUPER_TILED_TILE_TEXTURES=1 in the
    environment is needed to opt-in into using those.
  - Ensure that GStreamer is properly initialized before applying any multimedia
    handling quirks.
  - Fix PointerEvent behaviour for mouse events synthesized from touch inputs.
  - Fix drag-and-drop when dropping folders from a file manager into a web view.
  - Fix seeking and looping of media elements that set the "loop" property. 
  - Fix several crashes and rendering issues.