Make Windows ExceptionHandler::HandleException public

This is a fiddly little change, but Mozilla is using this patch so that we can
hook SetUnhandledExceptionFilter and ensure that third-party code does not set
the exception handler to something other than Breakpad's handler. This patch was
originally written in https://bugzilla.mozilla.org/show_bug.cgi?id=747213.

[Mark Mentovai]

I don’t like this at all. I’m sure there’s another way for you to achieve what
you’re looking for, such as getting the address of the exception handler
immediately after asking Breakpad to install a handler, and using that for your
subsequent comparisons. Another alternative would be to add code to Breakpad to
return (true/false) whether its own exception handler is set as active. Making
this function public just invites API abuse.

[Ted Mielczarek]

On 2012/09/17 15:49:19, Mark Mentovai wrote:
> I don’t like this at all. I’m sure there’s another way for you to achieve what
> you’re looking for, such as getting the address of the exception handler
> immediately after asking Breakpad to install a handler, and using that for
your
> subsequent comparisons. Another alternative would be to add code to Breakpad
to
> return (true/false) whether its own exception handler is set as active. Making
> this function public just invites API abuse.

I agree, this is not great. The lack of a GetUnhandledExceptionFilter API makes
this a bit annoying, since we have no way to get the address of this function
without calling SetUnhandledExceptionFilter, which I'd rather not do.

Would you be okay with an API like:
bool is_this_handler(LPTOP_LEVEL_EXCEPTION_FILTER filter) { return filter ==
HandleException; }

[Mark Mentovai]

Yeah, I’d prefer something like that.

[Ted Mielczarek]

On 2012/09/17 17:47:39, Mark Mentovai wrote:
> Yeah, I’d prefer something like that.

You know what? I'm just going to change our code to not require this. Sorry for
the churn.