Structured cloning has weird layering that is getting in the way of some changes I'd like to make.

Then move JSStructuredCloneWriter's callbacks, callback data, and refsHeld into its SCOutput's JSStructuredCloneData. This removes the loose fields from JSStructuredCloneWriter and allows using move construction to remove a bunch of code.

Comment on attachment 8969015 [details] [diff] [review] Allow synthetic clone buffers to contain transferables, Carrying over r=jorendorff on all these patches.

Comment on attachment 8969020 [details] [diff] [review] Use delegation rather than inheritance for the BufferList in JSStructuredCloneData, Review of attachment 8969020 [details] [diff] [review]: ----------------------------------------------------------------- Andrea, this is probably just a rubber stamp, but previously I only asked for (and received) feedback+ on this, so I'd like an r+ before landing. Thanks!

Pushed by sfink@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/897e368bab8c Allow synthetic clone buffers to contain transferables, r=jorendorff https://hg.mozilla.org/integration/mozilla-inbound/rev/9f5ed3cd4d91 Bulk up SCOutput by changing it from storing a bare BufferList to a full JSStructuredCloneData, r=jorendorff https://hg.mozilla.org/integration/mozilla-inbound/rev/b932696b192a Remove unused alternate callback option to JSAutoStructuredCloneBuffer::clear, r=jorendorff https://hg.mozilla.org/integration/mozilla-inbound/rev/c544503c6ae6 Comment the purpose of JSAutoStructuredCloneBuffer, r=jorendorff https://hg.mozilla.org/integration/mozilla-inbound/rev/544004ece6c4 Remove unused JSAutoStructuredCloneBuffer::copy, r=jorendorff https://hg.mozilla.org/integration/mozilla-inbound/rev/482a42df57ac Use delegation rather than inheritance for the BufferList in JSStructuredCloneData, r=jorendorff,r=baku

Pushed by sfink@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/837f9a0480fb tier 2 bustage followup - s/WriteBytes/AppendBytes/

https://hg.mozilla.org/mozilla-central/rev/897e368bab8c https://hg.mozilla.org/mozilla-central/rev/9f5ed3cd4d91 https://hg.mozilla.org/mozilla-central/rev/b932696b192a https://hg.mozilla.org/mozilla-central/rev/c544503c6ae6 https://hg.mozilla.org/mozilla-central/rev/544004ece6c4 https://hg.mozilla.org/mozilla-central/rev/482a42df57ac https://hg.mozilla.org/mozilla-central/rev/837f9a0480fb