Add additional definitions to JSSymbol

[nex3]

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[copybara-service]

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[copybara-service]

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[copybara-service]

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[srujzs]

You may need to resolve conflicts before gerrit picks up the latest commit as a patch that we can CQ+1 on.

[nex3]

Working on it, but unfortunately that means I need to do a bunch of recompiling so I can regenerate accurate IR tests. (Do these things really get a bunch of opaque numbers updated every time someone touches the JS interop library?)

[nex3]

Merge conflicts resolved.

[copybara-service]

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[copybara-service]

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[srujzs]

(Do these things really get a bunch of opaque numbers updated every time someone touches the JS interop library?)

dart2wasm emits JS methods that then makes the desired interop call for each unique interop method. To minimize code size, we just use a monotonically increasing number. I'm guessing they all increased by 18 because we added 18 interop methods (although I count only 17?).

What is surprising though is that we include all the SDK interop members even if they don't get used.

---

We add generated interop procedures into the Library that declares the interop member here:

sdk/pkg/dart2wasm/lib/js/method_collector.dart

Line 34 in 7bb5e4c

library.addProcedure(procedure);

.

When we're emitting the JS module, we iterate over all the Librarys in the program that have import or export pragmas:

sdk/pkg/dart2wasm/lib/functions.dart

Line 44 in 7bb5e4c

library.procedures.forEach(_importOrExport);

.

Importantly, in this later step, interop procedures that were not called in user libraries are no longer contained in the Library node. I have to assume TFA removed these procedures, but it isn't clear why it doesn't remove unused members in the SDK. @mkustermann, is this WAI? Does TFA not tree-shake SDK members?