Add catch_exception_tool

Add catch_exception_tool.

catch_exception_tool catches Mach exceptions. Currenlty, it simply
prints a message with some information about each exception it handles.
In the future, it will be tied to the minidump generator as well.

R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/f764db270fb24c3144e8e8811ea1a6621671a63f

[Mark Mentovai, 2014-09-16 21:50:21]

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

[Mark Mentovai, 2014-09-16 21:50:22]

This depends on https://codereview.chromium.org/574753003/.

[Robert Sesek, 2014-09-17 16:28:04]

https://codereview.chromium.org/579443005/diff/1/tools/catch_exception_tool.cc
File tools/catch_exception_tool.cc (right):

https://codereview.chromium.org/579443005/diff/1/tools/catch_exception_tool.c...
tools/catch_exception_tool.cc:125: int sig = (code[0] >> 24) & 0xff;
You've masked the code this way before. Would it be good to create a new
function to get these three values from a code instead of doing it inline, in
case this packing logic changes in the future?

[Mark Mentovai, 2014-09-17 16:31:22]

Yes, this is the next thing I was going to send out. Do you want me to merge it
into this change?

[Robert Sesek, 2014-09-17 16:32:04]

No, fine to refactor that separately. LGTM

[Mark Mentovai, 2014-09-17 19:40:18]

Committed patchset #1 (id:1) manually as f764db2 (presubmit successful).