chromium: connection sharing feature

Extend Client Socket Pool to allow sharing
of idle sockets between hosts with different names,
but with identical IPs.

Change-Id: Iffd1082d24ca7efccdca2db2e259f86e9779de49

Conflicts:

	net/socket/client_socket_pool_base.cc
	net/socket/client_socket_pool_base.h
	net/socket/transport_client_socket_pool.cc