Sam Rawlins c86194e544 Null-assert the value given to a Completer expecting a non-null value (flutter/engine#49053)
The code with out the null assertion is legal as per the type signature,
but will throw a runtime exception if the nullable value is null. To
make this exception more explicit, the value must be null-checked before
completing the completer with the value.

The analyzer will soon enforce such checks. See dart-lang/sdk#53253.

This PR is behaviorally a no-op.

Fixes https://github.com/flutter/flutter/issues/136775


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2024-02-27 17:27:24 -08:00
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