Previously, 'now' was set to the time `requestAnimationFrame()` was
called, and the EventLoop's 'now' was ignored. This was a little odd and
meant the time was always in the past.
In this commit we have optimized the handling of scroll offsets and
clip rectangles to improve performance. Previously, the process
involved multiple full traversals of the paintable tree before each
repaint, which was highly inefficient, especially on pages with a
large number of paintables. The steps were:
1. Traverse the paintable tree to identify all boxes with scrollable or
clipped overflow.
2. Gather the accumulated scroll offset or clip rectangle for each box.
3. Perform another traversal to apply the corresponding scroll offset
and clip rectangle to each paintable.
To address this, we've adopted a new strategy that separates the
assignment of the scroll/clip frame from the refresh of accumulated
scroll offsets and clip rectangles, thus reducing the workload:
1. Post-relayout: Identify all boxes with overflow and link each
paintable to the state of its containing scroll/clip frame.
2. Pre-repaint: Update the clip rectangle and scroll offset only in the
previously identified boxes.
This adjustment ensures that the costly tree traversals are only
necessary after a relayout, substantially decreasing the amount of work
required before each repaint.
A markdown file gets loaded as an inline content document by
`create_document_for_inline_content()`, for which the default document
URL is "about:error". That breaks the fragment links.
Overriding "about:error" URL by passing the URL of the just loaded
markdown file as an argument to `HTMLParser::run()` ensures that the URL
of the document is as expected.
Before this change, `set_needs_to_resolve_paint_only_properties()` was
only called after style invalidation. However, since relayout can be
triggered independently from style invalidation, we need to ensure that
paint-only properties are updated in that case too.
Implements following rule from CSS Overflow Module Level 3:
"The visible/clip values of overflow compute to auto/hidden
(respectively) if one of overflow-x or overflow-y is neither visible
nor clip."
When WebDriver asks to destroy a window, we can hit this case with no
active browsing context. This seems odd, but perhaps is a spec issue as
well. Just log to dbgln for now.
This aligns it better with the current state of the spec.
There's still some functions and data members that need moved into
Navigable or TraversableNavigable, but we can leave those for the next
cleanup PR.
This check has been if (false && stuff) for quite a while, since the
transition to Navigables. No one updates the BrowsingContext's session
history, so the check for it having an about blank document and only an
about blank document is always false.
The IPC layer between chromes and LibWeb now understands that multiple
top level traversables can live in each WebContent process.
This largely mechanical change adds a billion page_id/page_index
arguments to make sure that pages that end up opening new WebViews
through mechanisms like window.open() still work properly with those
extra windows.
When an element with an ID is added to or removed from the DOM, or if
an ID is added, removed, or changed, then we must reset the form owner
of all form-associated elements who have a form attribute.
We do this in 2 steps, using the DOM document as the messenger to handle
these changes:
1. All form-associated elements with a form attribute are stored on the
document. If the form attribute is removed, the element is removed
from that list as well.
2. When a DOM element with an ID undergoes any of the aforementioned
changes, it notifies the document of the change. The document then
forwards that change to the stored form-associated elements.
By replacing the `page_did_request_scroll_to()` calls with a request
to perform scrolling in the corresponding navigable, we ensure that
the scrolling of iframes will scroll within them instead of triggering
scroll of top level document.
