Add ElementResizeAction to Page (maybe there's a better place). It's
just a mousemove delegate that updates styles on the target element.
Add ChromeMetrics for zoom-invariant chrome like scrollbar thumb
thickness, resize gripper size, paddings, etc. It's not user-stylable
but separates basic concerns in a way that a visually gifted
designer unlike myself can adjust to taste.
These values are pre-divided by zoom factor so that PaintableBox can
continue using device_pixels_per_css_pixel calls as normal.
The adjusted metrics are computed on demand from Page multiple times
per paint cycle, which is not ideal but avoids lifetime management and
atomics. Maybe someone with more surety about the painting flow control
can improve this, but it won't be a huge win. If profiling shows
this slowing paints, then Ladybird is in good shape.
Update PaintableBox to draw the resize gripper and deconflict
the scrollbars. Set apropriate cursors for scrollbars and gripper in
mousemove. We override EventHandler's cursor handling because nothing
should ever come between a man and his resize gripper.
Chrome metrics use the CSSPixels class. This is good because it's
broadly compatible but bad because they're actually different units
when zoom is not 1.0. If that's a problem, we could make a new type
or just use double.
The existing `::unite_horizontally()` and `::unite_vertically()` tests
did not properly test the edge cases where left/top in the Rect were
updated, so they get re-arranged a bit.
The CenterRight and TopCenter alignment cases were
mistakenly identical due to a copy-paste error,
causing the function to behave unexpectedly.
Rather than attempting to fix it, remove aligned_within entirely.
Now most classes dictate how they are serialized and deserialized when
transmitted across LibIPC sockets. This also makes the IPC compiler
a bit simpler. :^)
Instead of passing the BufferStream, pass the Decoder. I'd like to stop
using BufferStream eventually anyway, so it's good to get it out of any
API's where it's in currently.
This shaves ~5 seconds off of a full build, not too bad. Also it just
seems nicer to push this logic out to classes. It could be better but
it's a start. :^)
