Fix crash in DL building
Fix one crash and some style changes.
This HTML crashed servo before. Key parts are `background-clip: content-box` and `direction: rtl`
```html
<!DOCTYPE html>
<html>
<style>
#span1 {
background-clip: content-box;
}
#span2
{
direction: rtl;
}
</style>
<span id="span1">Filler Text <span id="span2">txeT relliF</span></span>
</html>
```
Should I add this as a test? And where do I put this "does-it-crash?" test?
I find always passing rectangles by value a lot easier as it avoids many references and dereferences and I assume that the compiler will always use the faster one either way. If you don't like the change feel free to only merge the first commit.
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Style change in display_list/builder.rs to reduce
the number of & and * found in the code.
Rect<Au> are basically 4 integers so there is no
need to pass by reference.
Add an automatic test for border-image-outset with a gradient.
Convert two tests from UTF-8 LE with CRLF line endings to
UTF-8 with LF endings as the old files could not be viewed with servo.
Closes#16638
Implement corner clipping.
Remove PixelFormat from WebrenderImageInfo.
Use WebRender text shadow.
Remove MallocSizeOf and Deserialize for DL items.
Closes#19649, #19680, #19802
This uses floating-point (Layout) coordinates in where possible.
Replace NormalBorder struct with WebRender equivalent.
Remove ToPointF and ToRectF traits.
Convert border RepeatKeyword with ToLayout.
Add some definitions to malloc_size_of for WebRender types.
Move display_list_builder.rs and webrender_helpers.rs
along with the new file to components/layout/display_list/
Remove apparently unused IdType enum.
Only variant used was OverflowClip.
See #19676
