Add support for external webkit process to secure list

GF-1962:  Eliminate permission issue related to WebAppMgr using
an external webkit process.

Open-webOS-DCO-1.0-Signed-off-by: Roger Stringer <roger.stringer@palm.com>

Change-Id: I8958ed505ed7f41dd93b5d31449ff4f2cd9a1757