V8 perf: selection_call getting deoptimized

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Profiling turns up a lot of deopts in our render code:

These all have the reason listed as "Not optimized: Bad value context for arguments value"
Details here

I think what that means is that if we are going to use selection.call to call functions, all those functions should not have properties attached to them (or should have the same properties).

i.e. It's ok to selection.call(drawVertices, ...) but once we throw in something like selection.call(drawVertices.drawHover, ...) , the call sites are no longer monomorphic and all of our selection.call get deoptimized.

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Worth mentioning here that this might not be fixable.

All of our behaviors use the pattern selection.call(behavior) and selection.call(behavior.off). So that would need to change.

Also I haven't dug into it, but wouldn't surprise me if this pattern is common elsewhere in the d3 internals, and whether a single instance of this kind of call deopts all the selection.calls.

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stale