Previously, when a cache was invalidated and every tab/iframe issued a getStyles request, we previous needlessly accessed IndexedDB for each of these requests. It happened because 1) the global cachedStyles was created only at the end of the async DB-reading, 2) and each style record is retrieved asynchronously so the single threaded JS engine interleaved all these operations. It could easily span a few seconds when many tabs are open and you have like 100 styles.
Now, in getStyles: all requests issued while cachedStyles is being populated are queued and invoked at the end.
Now, in filterStyles: all requests are cached using the request's options combined in a string as a key. It also helps on each navigation because we monitor page loading process at different stages: before, when committed, history traversal, requesting applicable styles by a content script. Icon badge update also may issue a copy of the just issued request by one of the navigation listeners.
Now, the caches are invalidated smartly: style add/update/delete/toggle only purges filtering cache, and modifies style cache in-place without re-reading the entire IndexedDB.
Now, code:false mode for manage page that only needs style meta. It reduces the transferred message size 10-100 times thus reducing the overhead caused by to internal JSON-fication in the extensions API.
Also fast&direct getStylesSafe for own pages; code cosmetics
Styles are listed before actions by default. Actions are listed before
styles if `popup.stylesFirst` is false. A control for the option is shown
in "Manage" if `popup.stylesFirstUI` is true.
Two independent filters. One allows only styles that are enabled, the
other allows only styles that were written locally (that is, styles
without an update URL).
(1) `loadPrefs` was called with string instead of boolean
(2) Sense of boolean `popup.breadcrumbs.usePath` was inverted
(3) `loadPrefs` wasn't passing default to `getPrefs`
(4) `JSON.stringify(string)` added quotes to string
(5) Preferences `manage.enabledFirst`, `observer.observeFrameContent`, `observer.observeFrameLoad` aren't used
