Add child processes created outside Job object as peer processes.

Add child processes created outside Job object as peer processes.

This tracks non-job object processes (e.g. those created under
--allow-no-sandbox-job on Citrix and RDP RemoteApp) so policy
decisions can be made correctly by the broker.

BUG=480716,505813
TEST=sbox_integration_tests --gtest_filter=HandlePolicyTest.DuplicateHandle running an a RemoteApp on Win2k8r2
TEST=make sure printing and flash both work from Win2k8r2 as RemoteApp or Citrix XenApp 6.5 running Chrome as published application.

Review URL: https://codereview.chromium.org/1214933005

Cr-Commit-Position: refs/heads/master@{#336825}