@danfinlay This PR is off of your branch: https://github.com/MetaMask/metamask-extension/tree/i3076-UseStorageLocalInstead

I've made three changes:

• error handling in place of the TODO comments you had in background.js
• adds some null-safe property checks to the attempts to access the storage property in extension-store.js
• completes the tests you outlined for extensions-store-test.js

Feel free to accept or reject changes as is useful to you.