We currently might double-attach to the target in `BrowserHandler` since we iterate over all targets, and then subscribe to the additional event when target is getting initialized.
This patch fixes this race condition and should unblock the roll to r1177.
References #3995
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.
Juggler code had a bug where we subscribed to window and tab
events, but did not iterate collections of current windows and tabs.
As a result, we were sometimes failing to set viewport size for the
initial window, and implemented an artificial promise to workaround
the problem.
This patch:
- starts calling `onOpenWindow` and `onOpenTabListener` callbacks
for *all* windows and tabs - current and future, eliminating the
race condition.
This worked too well and we started overriding window sizes that
were set by users with `window.open(url, 'width=300;height=400')` (we
have a test for this). To fix this, we now plumb `CHROME_WITH_SIZE`
flag from appWindow and override viewport iff this flag is not set.
After this patch, we will use the `onTabOpened` event to move user
agent emulation to the browser-side.
References #3995
