Support generating minidumps from live processes on OS X

This patch implements ExceptionHandler::WriteMinidumpForChild, the same API
provided by the patches in:
http://breakpad.appspot.com/115002/show
http://breakpad.appspot.com/123001/show

Those have yet to land in the Breakpad repo, but I think it's useful API.

[Mark Mentovai]

lgo

http://breakpad.appspot.com/148001/diff/1/3
File src/client/mac/handler/exception_handler.cc (right):

http://breakpad.appspot.com/148001/diff/1/3#newcode332
Line 332: if (task_suspend(child) != KERN_SUCCESS)
ScopedTaskSuspend would be helpful here too.

http://breakpad.appspot.com/148001/diff/1/6
File src/client/mac/tests/exception_handler_test.cc (right):

http://breakpad.appspot.com/148001/diff/1/6#newcode47
Line 47: public:
1-space indent here.

http://breakpad.appspot.com/148001/diff/1/6#newcode126
Line 126: char machPortName[128];
mach_port_name

http://breakpad.appspot.com/148001/diff/1/6#newcode135
Line 135: close(fds[0]);
Put a comment here saying you’re in the child.

Put some blank lines in at strategic locations to break things up, too.

http://breakpad.appspot.com/148001/diff/1/6#newcode145
Line 145: (void)read(fds[1], &data, 1);
(void) not helpful.

http://breakpad.appspot.com/148001/diff/1/6#newcode180
Line 180: sleep(10000);
What’s this about?

[Ted Mielczarek]

http://breakpad.appspot.com/148001/diff/1/3
File src/client/mac/handler/exception_handler.cc (right):

http://breakpad.appspot.com/148001/diff/1/3#newcode332
Line 332: if (task_suspend(child) != KERN_SUCCESS)
On 2010/08/13 16:59:42, Mark Mentovai wrote:
> ScopedTaskSuspend would be helpful here too.

Is this something that's already written, or are you suggesting I write it?

http://breakpad.appspot.com/148001/diff/1/6
File src/client/mac/tests/exception_handler_test.cc (right):

http://breakpad.appspot.com/148001/diff/1/6#newcode145
Line 145: (void)read(fds[1], &data, 1);
On 2010/08/13 16:59:42, Mark Mentovai wrote:
> (void) not helpful.

Depending on the compiler, I've had compile errors telling me I'm not allowed to
ignore the return value. Doesn't seem to be the case here.

http://breakpad.appspot.com/148001/diff/1/6#newcode180
Line 180: sleep(10000);
On 2010/08/13 16:59:42, Mark Mentovai wrote:
> What’s this about?

Oops, I stuck that in there so I could easily look at the resulting dump, and
forgot to remove it. (Then spent 5 minutes this morning trying to figure out why
my test was hanging.)