fix: mobile Safari's ReferenceError

[sairoutine]

I encountered the same bug as #47.
The reason is that a new code does not use self.performance instead of performance.
I fixed it.

Thanks.

[mrdoob]

Is this still and issue on iOS10?

[sairoutine]

I don't have iOS10, but in my iOS 8.1, this is still occured.

[mrdoob]

I see I see. Would it be possible to not include the build in this PR. Seems to be causing conflicts.

[sairoutine]

I deleted the built file. Could you please merge this?

[pavle-goloskokovic]

+1 for merging this, got the same error on older version of Opera

[sairoutine]

@mrboob How about this PR?

[mrdoob]

Sorry for the delay... Is this still needed?

[sairoutine]

@mrdoob
I still maintain the app for iOS 8.1 as necessary.
It would be appreciated if you could merge this.

[sairoutine]

if you were not willing to add this code to your repository, I would take down this PR and fork this repo.

[mrdoob]

How many people use iOS 8.1?

[sairoutine]

Now in 2020, almost all iOS 8 share is 0.0%
https://www.statista.com/statistics/565270/apple-devices-ios-version-share-worldwide/