Revert 30938 - Add support for getting the real process id from within the su...

Revert 30938 - Add support for getting the real process id from within the suid sandbox. The browser processes gets the real process ids, so they look correct in the task manager. When it asks the zygote to reap a process, we use the process ids internal to the sandbox.

While we are at it, reap the sandbox process after it clones the zygote and figure out zygote's actual process id. Save the actual process id rather than that of the sandbox.

BUG=20012, 20714, 23072
TEST=Process IDs for renderers should be correct in the task manager and you should be able to use the end process button to kill them.
Review URL: http://codereview.chromium.org/262020

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=30939