Restore changes accidentally reverted in bikeshed conversion

[karlt]

One such change is the "Spec document unloading" PR, which was merged to index.html November 2017, for issue https://github.com/WebAudio/web-audio-api/issues/1139

Mention of unload was removed from index.html in the Bikeshed conversion commit, which was merged March 2018, and there was no mention in the new index.bs.

[padenot]

Telconf decision: put this one back, and try to find a way to find what else has been missed.

[padenot]

I'm going to rebase my old PR on the current text, and find paths that create promises that have been added since then, to add then to the [[pending promises]] array.

This must have been missed when re-basing in-flight PRs in between starting and merging the Bikeshed conversion work.

[padenot]

This has been sorted out in #2166. Hopefully it was the only one.

[karlt]

Thank you for fixing that.

I used w3m to convert to text the versions of index.html before and after the bikeshed and then ran patdiff -html <(sed s/’/\'/g index.c70964.w3m) <(sed s/’/\'/g index.e8f64d.w3m).

The key changes that came with the bikeshed conversion are listed below. I didn't find anything major that has been missed.

I assume these changes were intended:

• AudioContextOptions parameter to AudioContext constructor is no longer nullable.
• OfflineAudioContext oncomplete attribute is no longer readonly.
• OfflineAudioCompletionEventInit renderedBuffer attribute is no longer readonly.

These changes have since been corrected:

• Removal of default values for input and output parameters to AudioNode.connect() methods.
• ChannelSplitterNode constructor parameter type changed from ChannelSplitterOptions to ChannelSplitterNode.
• Removal of "The use of a curve that produces a non-zero output value for zero input value will cause this node to produce a DC signal even if there are no inputs connected to this node. This will persist until the node is disconnected from downstream nodes."
• Addition of extra AudioContext in BitCrusher Node and VU Meter Node.
• Removal of document unloading.

These have not been corrected, but don't seem significant:

• "Single input and output with single channel." > "Single input, single channel." in BypassProcessor.
• Deletion of "'s audio rendering thread" after "new AudioWorkletGlobalScope is created in association with the context" in AudioWorklet Sequence.
• "produce" -> "use" output in VU Meter Node.

This is now irrelevant because the state property no longer exists:

-|the node. The flag change is propagated by queueing a task on the control
-|thread to update the corresponding AudioWorkletNode's state property
-|accordingly.
+|the node. To propagate the flag change queue a task on the control thread to
+|update the corresponding AudioWorkletNode's state property accordingly.