Previously if you had a selection and you pressed the left/right arrow
key it would collapse the selection *and* perform the movement. This is
not how most text editors work and felt unnatural.
We were mimicking Firefox' behavior that whenever a programmatic change
to an <input>'s or <textarea>'s selection happened, the new selection
focus is brought into view by scrolling. Currently we run a layout
update synchronously for that to make sure we have the fragment's
correct dimensions, which caused a significant performance regression in
Speedometer.
Since this is non-standard behavior, let's mimic Chromium instead which
does not scroll at all - only for direct user initiated input such as
typing.
Relevant issues:
* https://github.com/whatwg/html/issues/6217
* https://bugzilla.mozilla.org/show_bug.cgi?id=232405
* https://issues.chromium.org/issues/41081857
If a node with `contenteditable=true/plaintextonly` is the child of an
editable node or an editing host, we should make it editable instead of
an editing host. This effectively merges nested editing hosts together,
which is how other browsers deal with this as well.
Gains us 5 WPT subtest passes in `editing`.
And make it a DOM::Node, not DOM::Element. This makes everything flow
much better, such as spec texts that explicitly mention "focused area"
as the fact that we don't necessarily need to traverse a tree of
elements, since a Node can be focusable as well.
Eventually this will need to be a struct with a separate "focused area"
and "DOM anchor", but this change will make it easier to achieve that.
We were constraining the focusing behavior for editing hosts a bit too
much; regardless of how the selection changed, if the start container is
inside an editing host and it's currently not focused, we should focus
it. This fixes focus stealing by other elements that set a selection
inside an editing host on a click event, for example.
Before this change, we were going through the chain of base classes for
each IDL interface object and having them set the prototype to their
prototype.
Instead of doing that, reorder things so that we set the right prototype
immediately in Foo::initialize(), and then don't bother in all the base
class overrides.
This knocks off a ~1% profile item on Speedometer 3.
We were using the anchor_node() as the boundary point node when
collapsing a selection, but the spec tells us to use the start and end
boundary point nodes.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
The main motivation behind this is to remove JS specifics of the Realm
from the implementation of the Heap.
As a side effect of this change, this is a bit nicer to read than the
previous approach, and in my opinion, also makes it a little more clear
that this method is specific to a JavaScript Realm.
