Note: Instead of exactly honoring the legacy -webkit-gradient(linear,...)
syntax, we aim to simply parse it into something that's approximately
equivalent for common use cases.
In the legacy -webkit-gradient(linear,...) syntax, authors provide *two
arbitrary points* to establish the direction of the gradient, whereas modern
linear-gradient() is simpler: it just takes a single "<side-or-corner>" point
and fills the box with a gradient in the direction of that side or corner.
Before this changeset, we parsed -webkit-gradient(linear,...) into a
slightly-less-legacy "-moz-linear-gradient" representation, so that we could
honor at least one of the author's specified points (since -moz-linear-gradient
accepts a single arbitrary point as the start of the gradient). But that
prevents us from deprecating -moz-linear-gradient, and it makes it impossible
to spec our emulation behavior in terms of modern standards.
So, this changeset is just changing our approximate representation so that it
can always be serializeable as a modern linear-gradient() expression.
In addition, I'm removing the reftest "webkit-gradient-approx-linear-1.html"
(whose behavior this patch is changing slightly) and I'm replacing it with a
new chunk in test_computed_style.html to more directly test this parsing
behaivor.
MozReview-Commit-ID: 6N1oKaGeOuE
--HG--
extra : rebase_source : b038205c700ea7d84afa12d7424df17e4a1ca9dc
