Fix crash in client_socket_pool_base.cc.

The CHECK that was being hit showed a real problem: group's IsEmpty
should take into account the pending requests queue too.

I also made IsEmpty check for connecting requests queue emptiness,
so we can be sure that IsEmpty really means empty.

TEST=Added a regression test ClientSocketPoolBaseTest.GroupWithPendingRequestsIsNotEmpty to net_unittests.
http://crbug.com/17985

Review URL: http://codereview.chromium.org/159597

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21988 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed