Andrey Lushnikov e28083974d
browser(firefox): simplify PageTarget lifecycle (#4014)
As of today, we create `PageTarget` instances whenever we get a
sync IPC from the content process. This, however, breaks an invariant
that `browserContext.pages` always has all pages (and *browsing contexts* - not to be confused with *browser contexts*), associated with browser context. This invariant will be especially important when we move
user agent emulation to browser-side.

This patch makes `PageTarget` lifecycle symmetrical:
- `PageTarget` instance is created when tab is opened
- `PageTarget` is destroyed when tab is crashed or closed

This should also fix a bunch of race conditions with persistent mode, since sometimes we arrive to the window after its
initialization.

Drive-by: straighten viewport management and put a nice descriptive comment.
2020-09-30 02:10:34 -07:00
..
2019-11-19 10:58:15 -08:00