**Preamble**
1. We're trying to setup a windows-based github self-hosted runner in the
playwright-internal repo.
1. Commands on Windows are mandated to have total arguments length
less then 32767 characters.
1. On windows, github self-hosted runner framework puts repository
checkout at `c:\w\playwright-internal\playwright-internal`
1. Our scripts create a checkout at
`c:\w\playwright-internal\playwright-internal\browser_patches\firefox\checkout`
1. One of the scripts in Firefox buildsystem tries to execute a command,
passing lots of absolute paths to various webidl's
1. The command fails due to restriction in (2)
**Problem**
Firefox build fails since checkout is deeply nested and hits max arg
size on windows.
**Solution**
This patch introduces a new variable `FF_CHECKOUT_PATH` that is
respected by all browser-related scripts. This way we'll be able
to checkout firefox to `c:\firefox` and avoid hitting long arguments
limit.
The `$PROGRAMFILES` variable is defined per the bitness of the
application: 32-bit shells get `C:\Program Files (x86)`, whereas
64-bit shells get `C:\Program Files`.
Visual Studio, however, has only 32-bit build and is always located in
the `C:\Program Files (x86)` folder.
This patch fixes `//browser_patches/firefox/build.sh` on 64-bit windows
shell.
browser(firefox): ensure detachedFromTarget is always sent
LinkedBrowser can throw when removing listeners in PageTarget.dispose,
and that prevents BrowserHandler from sending Browser.detachedFromTarget.
Using a try-catch seems good enough.
Currently, browser.version() returns `83.0`, whereas launching firefox
with `--version` flag returns `83.0b3`. This patch alings protocol's
`Browser.version()` with flag output.
Somehow, we get WebProgress state changes when worker is loaded
with a blob url. This messes up frame navigation detection.
Luckily, it's easy to filter out non-document state changes.
As Joel noticed recently, MessageManager in firefox doesn't guarantee
message delivery if the opposite end hasn't been initialized yet. In
this case, message will be silently dropped on the ground.
To fix this, we establish a handshake in SimpleChannel to make sure that
both ends are initialized, end buffer outgoing messages until this
happens.
Drive-by: serialize dialog events to only deliver *after* the
`Page.ready` protocol event. Otherwise, we deliver dialog events to the
unreported page.
We try to avoid closing firefox too early, fearing that this
might terminate clean shutdown sequence.
Usually we assume that `Browser.enable` is called before `Browser.close`
- however, this is not the case in certain tests. So we have to
ensure browser initialization in `Browser.close` as well.
In my local tests, this fixes the Firefox Pipe problem: it looks like
we were closing browser too quickly.
