The spec states that updates to descriptors in a `@font-face` rule
should be reflected in the connected `FontFace`'s attributes.
Previously this was achieved by directly accessing those descriptors
when calling the attribute getters, but this has a couple of issues:
a) The changes are only reflected if we use the accessors (i.e.
`FontFace::family()` rather than `FontFace::m_family`) which isn't
the case everywhere
b) The changes aren't persisted after the `FontFace` is disconnected
from it's `CSSFontFaceRule`
To fix these issues we now reparse and store the `FontFace`'s attributes
whenever the `CSSFontFaceRule`'s descriptors change.
Previously we would run it once within `set_src()` and then again within
`set_property()` which would lead to us creating two new `FontFace`s
instead of just one
This holds the boilerplate that's needed by any CSSStyleDeclaration
subclass that holds Descriptors. CSSFontFaceDescriptors now only has to
worry about initialization and its own exposed properties.
We have two different code paths that implement the "parse a CSS
declaration block" algorithm, for properties and descriptors. COmbining
them isn't straightforward, and doesn't seem especially useful.
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.
