mac: Add --use-system-default-handler option to crashpad_handler

mac: Add --use-system-default-handler option to crashpad_handler

This is a weird option that causes crashpad_handler to discard the crash
handler it inherited and replace it with the system default. Its use is
not recommended.

BUG=chromium:538373
R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/08e5e10167b02de7379d3cd20616bebeeb39c693

[Mark Mentovai, 2015-10-05 19:56:12]

mark@chromium.org changed reviewers:
+ rsesek@chromium.org

[Mark Mentovai, 2015-10-05 19:56:12]

I don’t like the option name, but I couldn’t come up with anything descriptive,
so I just cribbed the function name.

[Robert Sesek, 2015-10-05 21:32:31]

Should we be adding options whose use is not recommended? Were you only using
this for testing?

[Mark Mentovai, 2015-10-05 22:23:18]

This is for a better fix to bug chromium:538373. Rather than having the
relauncher process clear its handler, I’m going to have it start its own
crashpad_handler with this option. This option will disassociate the new
crashpad_handler from the crashpad_handler running from the disk image, making
it possible to unmount the disk image without having to lose crash coverage in
the relauncher process.

[Mark Mentovai, 2015-10-05 22:23:59]

I thought about not documenting it in the man page or --help, but I decided
against it because it’s worth having a description of what it actually does and
why it does that somewhere.

[Robert Sesek, 2015-10-05 22:28:07]

lgtm

[Mark Mentovai, 2015-10-05 22:28:46]

No thoughts on better naming?

[Robert Sesek, 2015-10-05 22:29:47]

On 2015/10/05 22:28:46, Mark Mentovai wrote:
> No thoughts on better naming?

--use-system-exception-handler ?

[Mark Mentovai, 2015-10-05 22:31:50]

Is there anything concise that says “use this for crashpad_handler”? My problem
with these names is that they could imply that the system handler is being used
instead of crashpad_handler, which isn’t true.

[Mark Mentovai, 2015-10-05 22:53:22]

Updated to use --reset-own-crash-exception-port-to-system-default as discussed.

The long name discourages use!

[Mark Mentovai, 2015-10-06 18:15:37]

Committed patchset #4 (id:50001) manually as
08e5e10167b02de7379d3cd20616bebeeb39c693 (presubmit successful).