Resolve getSW() to a matching waiting SW

[philipwalton]

R: @jeffposnick

Fixes #1957

This PR updates the logic for how an "own" service worker is resolved in workbow-window as follows:

If a service worker with a matching scriptURL was already waiting to activate at registration time, it is considered to be the "own" service worker and thus will be the service worker getSW() resolves to.

In cases where there's an active and waiting service worker at registration time with a matching scriptURL, getSW() will resolve to the waiting service worker because it's the one that was registered most recently.

[workbox-pr-bot]

PR-Bot Size Plugin

Changed File Sizes

File	Before	After	Change	GZipped
packages/workbox-window/build/workbox-window.dev.umd.js	30.51 KB	30.35 KB	-1%	8.05 KB
packages/workbox-window/build/workbox-window.prod.umd.js	4.66 KB	4.54 KB	-3%	1.81 KB

New Files

No new files have been added.

All File Sizes

View Table

File	Before	After	Change	GZipped
packages/workbox-background-sync/build/workbox-background-sync.prod.js	3.38 KB	3.38 KB	0%	1.46 KB
packages/workbox-broadcast-update/build/workbox-broadcast-update.prod.js	1.86 KB	1.86 KB	0%	933 B
packages/workbox-build/build/_types.js	41 B	41 B	0%	61 B
packages/workbox-build/build/index.js	3.64 KB	3.64 KB	0%	1.36 KB
packages/workbox-cacheable-response/build/workbox-cacheable-response.prod.js	579 B	579 B	0%	344 B
packages/workbox-cli/build/app.js	5.58 KB	5.58 KB	0%	1.98 KB
packages/workbox-cli/build/bin.js	1.16 KB	1.16 KB	0%	580 B
packages/workbox-core/build/workbox-core.prod.js	5.34 KB	5.34 KB	0%	2.29 KB
packages/workbox-expiration/build/workbox-expiration.prod.js	2.83 KB	2.83 KB	0%	1.24 KB
packages/workbox-google-analytics/build/workbox-offline-ga.prod.js	1.89 KB	1.89 KB	0%	898 B
packages/workbox-navigation-preload/build/workbox-navigation-preload.prod.js	652 B	652 B	0%	317 B
packages/workbox-precaching/build/workbox-precaching.prod.js	4.25 KB	4.25 KB	0%	1.71 KB
packages/workbox-range-requests/build/workbox-range-requests.prod.js	1.51 KB	1.51 KB	0%	758 B
packages/workbox-routing/build/workbox-routing.prod.js	3.38 KB	3.38 KB	0%	1.47 KB
packages/workbox-strategies/build/workbox-strategies.prod.js	4.86 KB	4.86 KB	0%	1.19 KB
packages/workbox-streams/build/workbox-streams.prod.js	1.38 KB	1.38 KB	0%	678 B
packages/workbox-sw/build/workbox-sw.js	1.33 KB	1.33 KB	0%	740 B
packages/workbox-webpack-plugin/build/generate-sw.js	5.29 KB	5.29 KB	0%	1.84 KB
packages/workbox-webpack-plugin/build/index.js	349 B	349 B	0%	255 B
packages/workbox-webpack-plugin/build/inject-manifest.js	7.22 KB	7.22 KB	0%	2.48 KB
packages/workbox-window/build/workbox-window.dev.umd.js	30.51 KB	30.35 KB	-1%	8.05 KB
packages/workbox-window/build/workbox-window.prod.umd.js	4.66 KB	4.54 KB	-3%	1.81 KB

Workbox Aggregate Size Plugin

8.77KB gzip'ed (58% of limit)
22.04KB uncompressed

[jeffposnick]

👍