Based on FranklinDM's follow-up for the issue.
This would require browser FE changes, particularly removing the associated
code in `tabbrowser.xml`, however, that was already done in Pale Moon previously.
Other front-end applications may need to take note, though.
Based on changes from the following bugs:
* Bug 696398 - Need an api to analyze panning performance
* Bug 800031 - Include paint time in tab switch telemetry
* Bug 820167 - Enable performance measurement of tab animation
* Bug 826383 - Improve Start/Stop FrameTimeRecording for telemetry usage
I could have done this through a CSSLoader to allow all CSS unit quirks but
I wasn't planning to start passing around document and element references
everywhere, so instead just did it manually by accepting numbers/floats in
addition to pixel and percent.
This restores support for using HTML tag styling of margins on the body.
Reftests post bug still pass for dynamic changes, so does the newly-added
test for body margins and frames that tests the old styling method.
This also removes the reftest list for stylo testing for obvious reasons.
This adds the later spec revision's contentBoxSize and borderBoxSize, and the
inlineSize and blockSize concepts.
The older spec contentRect remains functional as well for backwards
compatibility with the earlier spec (that was IMHO perfectly fine as it was...)
GetNodeDepth() is a specialized version for ResizeObserver to get the depth of
a node across Shadow DOM. It's better to have this in ResizeObserver.cpp
instead of the generic ContentUtils.
Also updated the function to bypass the shadow root itself and not count it
because ResizeObserver doesn't observe the shadow root and only needs the
relative depths among all observed targets. IOW we use the flattened tree here.
This PR passes all current tests for this feature, and implements the "prefers-color-scheme" media query as an enumerated keyword that is controlled by an integer preference.
Currently, the possible options are 0 to see a website's fallback code and essentially behave like this isn't implemented (our current behavior), 1 to express a preference for a light theme (the default for spec reasons), and 2 to express a preference for a dark theme. Over time, this list may expand to include other preferences like a preference for a sepia theme or something, and this leaves us prepared for that future.
This is probably the last thing we will ship (if ever) since it needs the most
spec and implementation work for arbitrary use that is pretty far into a corner.
This preference controls whether authors are allowed to specify animations
without a 0% or 100% keyframe.
We intend to ship this but it isn't implemented yet (needs a follow-up) but this
preference acts as a safeguard in case we discover we need to disable it once
it's implemented.
ScrollbarStyles contains values of overflow, (over)scroll-behavior, etc.
The only one which is marginally related to scroll _bars_ is overflow, which can
be used to hide scrollbar (by making an element not scrollable) or enforce the
scrollbar to display.
It makes more sense to be called ScrollStyles as it's mainly concerning behavior
of scrolling, not scrollbars. Also, with the addition of scrollbar width
properties, the current name can be confusing.
