Per tab storage for settings & values

[ffoodd]

Related to #292, we need to store tools status and values for each tab before making webextension the main way to use a11y.css.

This is somehow working in Nightly with my profile (extensions and custom config) but not in an empty profile:

function storeTextSpacingStatus(strStatus) {
	// Get a11y.css stored levels
	let getStatus = browser.storage.local.get("textSpacingStatus");
	getStatus.then(
		// when we got something
		(item) => {
			if (item && item.textSpacingStatus) {
				// Get current tab ID
				browser.tabs.query({ active: true, currentWindow: true }).then((tabs) => {
					// Get current stored value
					let textSpacingStatus = item.textSpacingStatus;
					// Add or replace current tab's value
					textSpacingStatus[tabs[0].id] = {"status": strStatus};
					// And set it back to the storage
					let setting = browser.storage.local.set({ textSpacingStatus });
					setting.then(null, onError); // just in case
				});
			}
		}
	);
}

I wasn't able to find out why this is working… Or rather why this is not working with a new profile.

FWIW, Mozilla's webextension-polyfill is loaded everywhere within webextension.Please help :D

[ffoodd]

Might be somehow related: mozilla/webextension-polyfill#102

[ffoodd]

Working in Firefox and Chromium next to #352