Use defaults for CSSMatrixComponentOptions

[darrnshn]

Fixes #612 . Changes behaviour: you can no longer pass in an option with null is2D.

Hi @tabatkins , PTAL

[tabatkins]

Why'd you make it required? That kinda clashes with providing a default value for it. ^_^

[darrnshn]

Oh oops, I thought required would make is2D not nullable. Fixed.

[tabatkins]

It was never nullable (that would have required a boolean?), it just could have been not passed before; adding a default value prevents that.

[darrnshn]

@tabatkins Hi Tab, it appears that this changes behaviour in a way that I didn't expect.

Before, we had two possibilities:

1. Don't pass in options. is2D is inferred from matrix.is2D.
2. Pass in options. is2D is set to options.is2D.

It seems that with this change, the first possibility changes to:

1. Don't pass in options. is2D is false (the default value).

I didn't expect this because I thought options was an optional argument, we would still have the "infer" code path, but it looks like IDL magic has made it impossible.

Is this the intended behaviour? Or is this a bug with the Blink IDL?

[tabatkins]

Ah, you're right, that is a behavior change. We should revert this and just address the issue more directly, then.