By caching the SkImage that is reused across repaints, we allow Skia t
optimize GPU texture caching.
ImmutableBitmap is chosen to own the SkImage because it guarantees that
the underlying pixels cannot be modified. This is not the case for
Gfx::Bitmap, where invalidating the SkImage would be challenging since
it exposes pointers to underlying data through methods like scanline().
This change makes WebGL to use LibGL only in SerenityOS, and the
platform's OpenGL driver in Ladybird if it is available.
This is implemented by introducing wrapper class between WebGL and
OpenGL calls. This way it will also be possible to provide more
complete support in Ladybird even if we don't yet have all needed
calls implemented in LibGL.
For now, the wrapper class makes all GL calls virtual. However, we
can get rid of this and implement it at compile time in case of
performance problems.
