Buffer modifications to virtual stylesheets (#618)

* Fix sheet insertion

Restore skip duration

Use virtualStyleRulesMap to re-populate stylesheet on Flush event

Clear virtualStyleRulesMap after flush applied

* Support rule deletion in virtual processing

* Simply restoreNodeSheet with early aborts

* Encountered a bug where firstFullSnapshot was played twice because timer was immediately started and reached the snapshot before the setTimeout returned

* Ignoring a FullSnapshot needs to be a one-time only thing, as otherwise we'll ignore it after scrubbing (restarting play head at a particular time). This is a problem if mutations have altered the player state, and we try to replay those mutations, so we e.g. try to remove an element that has already been removed because we haven't reset the FullSnapshot state

* Some `npm run typings` related fixups

* add basic html snapshot functionality

* move restoreNodeSheet to it's own module

* Refactor virtual style rules to buffer changes.
Only applies changes on flush.

`virtualStyleRulesMap` now works with strings instead of CSSRules.
CSSRules can only be via made `.insertRule` on CSSStyleSheet in most browsers.
And `new CSSStyleSheet()` only works in Chrome currently.

* remove unused code

* move VirtualStyleRules from CSSRule to string in tests

* correct paths for tests

* naming

* create and restore style snapshots for virtual nodes

* update replayer snapshot

* move storeCSSRules to virtual-styles.ts

* try/catch access to .sheet in case of access errors

* clean up tests

Co-authored-by: Vladimir Milenko <vladimir.milenko@uber.com>
Co-authored-by: Eoghan Murray <eoghan@getthere.ie>

package.json

@@ -5,7 +5,8 @@
   "scripts": {
     "prepare": "npm run prepack",
     "prepack": "npm run bundle",
-    "test": "npm run bundle:browser && cross-env TS_NODE_CACHE=false TS_NODE_FILES=true mocha -r ts-node/register test/**/*.test.ts",
+    "test": "npm run bundle:browser && cross-env TS_NODE_CACHE=false TS_NODE_FILES=true mocha -r ts-node/register -r ignore-styles -r jsdom-global/register test/**.test.ts",
+    "test:headless": "npm run bundle:browser && cross-env TS_NODE_CACHE=false TS_NODE_FILES=true PUPPETEER_HEADLESS=true mocha -r ts-node/register -r ignore-styles -r jsdom-global/register test/**.test.ts",
     "test:watch": "PUPPETEER_HEADLESS=true npm run test -- --watch --watch-extensions js,ts",
     "repl": "npm run bundle:browser && cross-env TS_NODE_CACHE=false TS_NODE_FILES=true ts-node scripts/repl.ts",
     "bundle:browser": "cross-env BROWSER_ONLY=true rollup --config",
@@ -39,14 +40,20 @@
   "devDependencies": {
     "@types/chai": "^4.1.6",
     "@types/inquirer": "0.0.43",
+    "@types/jsdom": "^16.2.12",
     "@types/mocha": "^5.2.5",
     "@types/node": "^10.11.7",
     "@types/puppeteer": "^5.4.3",
     "chai": "^4.2.0",
     "cross-env": "^5.2.0",
+    "fast-mhtml": "^1.1.9",
+    "ignore-styles": "^5.0.1",
     "inquirer": "^6.2.1",
     "jest-snapshot": "^23.6.0",
+    "jsdom": "^16.6.0",
+    "jsdom-global": "^3.0.2",
     "mocha": "^5.2.0",
+    "node-libtidy": "^0.4.0",
     "prettier": "2.2.1",
     "puppeteer": "^9.1.1",
     "rollup": "^2.3.3",