High CPU usage in Nifty Wallet

[bitcoin-buble]

If you are reporting a problem with Nifty Wallet, please include the following information:

What browser and version did you use?

Chrome Version 69.0.3497.100 (Official Build) (64-bit)

What operating system did you use?

OSX
v10.13.6 (17G65)
(High Sierra)
MacBook Pro (Retina, 15-inch, Mid 2015)

Do you have screenshots showing the problem?

What is your issue?

I've noticed high CPU usage of the nifty wallet extension. I believe this may be related to these issues in the main metamask repo:
MetaMask#4074

This PR fixes two memory leak issues:
MetaMask#5228

Would it be possible to merge this from the main metamask repo?

Cheers

[bitcoin-buble]

After restart (before logging in to nifty)

After restart (after logging in)