WebKitGTK 2.51.3 released!

This is a development release leading toward 2.52 series.

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 the variable 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.

Thanks to all the contributors who made possible this release.