When done with crash-dumping, we need to terminate the application. Calling...

When done with crash-dumping, we need to terminate the application. Calling
tgkill() is not necessarily possible, as a sandbox might block this call.
This changelist tries different approaches depending on whether we received
a synchronous or an asynchronous signal. This fixes unittest failures and
also runs correctly in sandbox'd environments.

TEST=ran unittest, and opened about:crash in sandbox'd Chrome
BUG=395
A=markus@chromium.org
Original review: http://breakpad.appspot.com/159001

Committed: http://code.google.com/p/google-breakpad/source/detail?r=656

[Lei Zhang (chromium)]

Committing your patch.

[markus]

Just for the record: LGTM