Only attempt to clear measures if we created the measure

[chrisui]

This fixes an issue where if we decided not to create a measurement we would clear ALL measurements from the performance entry buffer due to passing undefined as the entry name.

The original bug here means any performance entries the user might have in their application will be inadvertently nuked.

For reference see the performance.clearMeasures spec.

Todo

• Test/s incoming (would love some help in finding where to add such a test!)

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[chrisui]

Would love some assistance in targeting where to add a test for this. Can't seem to find any existing tests to add a new case to.

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[gaearon]

This seems fine as is, thanks! We don’t need a test because this code will be deleted in the next release (the perf integration is in a different place in Fiber). I think the new code doesn’t have this issue, but you can check ReactDebugFiberPerf to make sure.

I’ll make a note to cherry-pick this commit in 15.6.

[chrisui]

@gaearon Thanks for the quick turnaround Dan!