Add third_party/pexpect

Add third_party/pexpect

To be used to script end-to-end tests on Windows.

Follows https://codereview.chromium.org/1396943002.

R=mark@chromium.org
BUG=crashpad:20, crashpad:46, crashpad:52

[scottmg, 2015-10-08 23:36:28]

Not sure how you feel about importing this.

The actual tests are in the subsequent CL here
https://codereview.chromium.org/1397833004 .

It seems to work fairly well (just kind of works, handles timeouts, etc.), but
it's also a big blob of code to pull.

Another possible approach to avoid this, cdb also has a -c command line argument
which runs commands as if they were typed. So, in the above CL, we could use
that, passing it command lines like -c ".excr;q", then capture the output, and
write some regex-y code to look for a set of patterns in sequence.

[scottmg, 2015-10-09 17:22:26]

On 2015/10/08 23:36:28, scottmg wrote:
> Not sure how you feel about importing this.
> 
> The actual tests are in the subsequent CL here
> https://codereview.chromium.org/1397833004 .
> 
> It seems to work fairly well (just kind of works, handles timeouts, etc.), but
> it's also a big blob of code to pull.
> 
> Another possible approach to avoid this, cdb also has a -c command line
argument
> which runs commands as if they were typed. So, in the above CL, we could use
> that, passing it command lines like -c ".excr;q", then capture the output, and
> write some regex-y code to look for a set of patterns in sequence.

Yeah, I think I'll do this instead. Closing this CL, and I'll update the follow
on.