Use slots instead of directly referencing the attributes

[padenot]

This does not change any behaviour. I did not do VideoFrame yet because it's moving too much, I'll do it after.

This is split in multiple commit, to make it a lot easier to review.

This fixes almost all of #184, but will need a follow-up for VideoFrame.

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Preview | Diff

[chcunningham]

Looks great!

I thought I read somewhere that the style for attribute getters was to say "the getter steps...", but I can't find where I read that and I prefer the style you've used for the simple getters.

VideoFrame should mostly have slots defined already, but maybe I misunderstand what you're planning? You might wait for that one until after the #208 lands... if you're planning lots of churn the merge could get ugly.

[padenot]

VideoFrame should mostly have slots defined already, but maybe I misunderstand what you're planning? You might wait for that one until after the #208 lands... if you're planning lots of churn the merge could get ugly.

Simply a proofreading to make sure we're good and fix any typos, like the ImageDecoder/complete above, almost nothing.