Add ChildPortHandshake and its test

Add ChildPortHandshake and its test.

ChildPortHandshake is the most generic system yet to allow child
processes to provide their parents with Mach rights. These are
ordinarily expected to be send rights to the children’s own task ports,
or send rights to servers that the children hold receive rights to.

This updates DEPS to pull mini_chromium 1d3523dbda93, which includes
base::mac::ScopedMachPortSet.

TEST=util_test ChildPortHandshake.*
R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/85c9318597d74c6d33afa88679e88e5d3394526c

[Mark Mentovai, 2014-11-24 20:37:48]

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

[Mark Mentovai, 2014-11-24 20:37:48]

This depends on:

https://codereview.chromium.org/752243002/ (child_port Mach subsystem)
https://codereview.chromium.org/754123002/ (ChildPortServer)
https://codereview.chromium.org/756653004/ (LoggingWriteFD())

[Robert Sesek, 2014-11-25 18:29:27]

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
File util/mach/child_port_handshake.h (right):

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:61: //! child disassociates from the parent
with a double fork(), and the actual
For how long is the token valid? If a process does a double fork(), can it reuse
the secret?

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:65: //! end-of-file (no readers) condition .
Once detected, it will stop its
nit: space before .

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:84: ~ChildPortHandshake();
override ?

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:133: //!     handshake. This is an
implementation detail of RunClient and is only
The alternative to this would be to move this into protected:, friend the
fixture, and write wrappers.

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:160: //! \brief Runs the client.
If this isn't internal, move this above the internal ones (unless you take the
above suggestion).

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:183: static void RunClient(int pipe_read,
Should this return the status of the check-in?

[Mark Mentovai, 2014-11-25 19:20:30]

Updated.

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
File util/mach/child_port_handshake.h (right):

https://codereview.chromium.org/756603003/diff/1/util/mach/child_port_handsha...
util/mach/child_port_handshake.h:84: ~ChildPortHandshake();
Robert Sesek wrote:
> override ?

It’s not, though.

[Robert Sesek, 2014-11-25 19:31:45]

LGTM

[Mark Mentovai, 2014-11-25 19:56:13]

Committed patchset #3 (id:40001) manually as
85c9318597d74c6d33afa88679e88e5d3394526c (presubmit successful).