Call bind() to get the right this in precaching's plugins

[jeffposnick]

R: @philipwalton

Fixes #1927 by properly bind()ing to the Plugin instance.

This also adds to the integration test for workbox-precaching to ensure that the addPlugins() flow has better test coverage.

[philipwalton]

I'm assuming that updating the static sw-1.js file tests that this works, but what about explicitly adding a unit test to verify that cacheWillUpdate is called with the correct this context.

[jeffposnick]

Sure, I just added one.

[philipwalton]

👍

[workbox-pr-bot]

PR-Bot Size Plugin

Changed File Sizes

File	Before	After	Change	GZipped
packages/workbox-precaching/build/workbox-precaching.prod.js	4.24 KB	4.25 KB	+0%	1.71 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	3.60 KB	3.60 KB	0%	1.56 KB
packages/workbox-broadcast-update/build/workbox-broadcast-update.prod.js	1.85 KB	1.85 KB	0%	930 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	5.46 KB	5.46 KB	0%	2.36 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	4.24 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%	677 B
packages/workbox-sw/build/workbox-sw.js	1.33 KB	1.33 KB	0%	741 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	30.37 KB	30.37 KB	0%	8.01 KB
packages/workbox-window/build/workbox-window.prod.umd.js	4.65 KB	4.65 KB	0%	1.80 KB

Workbox Aggregate Size Plugin

8.83KB gzip'ed (59% of limit)
22.15KB uncompressed

[coveralls]

Coverage remained the same at 82.837% when pulling a932efc on precaching-plugin-bind into d76e770 on master.