Revert of Remove reference counting from HttpNetworkSession.

Revert of Remove reference counting from HttpNetworkSession. (patchset #11 id:430001 of https://codereview.chromium.org/1298253002/ )

Reason for revert:
Causing net tests to fail on a couple memory FYI bots with a stack that makes no sense, as there should be SpdySessionPool created until after SetUp has completed:

[----------] 488 tests from NextProto/HttpNetworkTransactionTest
[ RUN      ] NextProto/HttpNetworkTransactionTest.Basic/0
[4832:3079:0911/175605:3116231085741:FATAL:weak_ptr.h(211)] Check failed: get() != NULL.
0   net_unittests                       0x0000000100e4e4a3 base::debug::StackTrace::StackTrace() + 19
1   net_unittests                       0x0000000100e4e4c9 base::debug::StackTrace::StackTrace() + 9
2   net_unittests                       0x0000000100e66ad3 logging::LogMessage::~LogMessage() + 67
3   net_unittests                       0x0000000100e662d9 logging::LogMessage::~LogMessage() + 9
4   net_unittests                       0x00000001004a8d3a base::WeakPtr<net::HttpServerProperties>::operator->() const + 90
5   net_unittests                       0x0000000101257267 net::SpdySessionPool::OnIPAddressChanged() + 439
6   net_unittests                       0x00000001010422a7 _ZN4base20DispatchToMethodImplIN3net21NetworkChangeNotifier17IPAddressObserverEMS3_FvvEJEJEEEvPT_T0_RKNS_5TupleIJDpT1_EEENS_13IndexSequenceIJXspT2_EEEE + 23
7   net_unittests                       0x0000000101042289 _ZN4base16DispatchToMethodIN3net21NetworkChangeNotifier17IPAddressObserverEMS3_FvvEJEEEvPT_T0_RKNS_5TupleIJDpT1_EEE + 9
8   net_unittests                       0x00000001010420ea _ZNK4base8internal13UnboundMethodIN3net21NetworkChangeNotifier17IPAddressObserverEMS4_FvvENS_5TupleIJEEEE3RunEPS4_ + 26
9   net_unittests                       0x0000000101041b3b _ZN4base22ObserverListThreadSafeIN3net21NetworkChangeNotifier17IPAddressObserverEE13NotifyWrapperIMS3_FvvENS_5TupleIJEEEEEvPNS4_19ObserverListContextERKNS_8internal13UnboundMethodIS3_T_T0_EE + 203
10  net_unittests                       0x0000000101041fb5 _ZN4base8internal15RunnableAdapterIMNS_22ObserverListThreadSafeIN3net21NetworkChangeNotifier17IPAddressObserverEEEFvPNS6_19ObserverListContextERKNS0_13UnboundMethodIS5_MS5_FvvENS_5TupleIJEEEEEEE3RunEPS6_RKS8_SG_ + 69
11  net_unittests                       0x0000000101041efb _ZN4base8internal12InvokeHelperILb0EvNS0_15RunnableAdapterIMNS_22ObserverListThreadSafeIN3net21NetworkChangeNotifier17IPAddressObserverEEEFvPNS7_19ObserverListContextERKNS0_13UnboundMethodIS6_MS6_FvvENS_5TupleIJEEEEEEEENS0_8TypeListIJRKPS7_RKS9_SH_EEEE8MakeItSoESK_SO_SQ_SH_ + 75
12  net_unittests                       0x0000000101041e99 _ZN4base8internal7InvokerINS_13IndexSequenceIJLm0ELm1ELm2EEEENS0_9BindStateINS0_15RunnableAdapterIMNS_22ObserverListThreadSafeIN3net21NetworkChangeNotifier17IPAddressObserverEEEFvPNSA_19ObserverListContextERKNS0_13UnboundMethodIS9_MS9_FvvENS_5TupleIJEEEEEEEEFvPSA_SC_SK_ENS0_8TypeListIJSO_SC_SI_EEEEENSQ_IJNS0_12UnwrapTraitsISO_EENST_ISC_EENST_ISI_EEEEENS0_12InvokeHelperILb0EvSN_NSQ_IJRKSO_RKSC_SK_EEEEEFvvEE3RunEPNS0_13BindStateBaseE + 105
13  net_unittests                       0x00000001000d31b4 base::Callback<void ()()>::Run() const + 20
14  net_unittests                       0x0000000100e4eea5 base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask const&) + 165
15  net_unittests                       0x0000000100e751fa base::MessageLoop::RunTask(base::PendingTask const&) + 282
16  net_unittests                       0x0000000100e7538c base::MessageLoop::DeferOrRunPendingTask(base::PendingTask const&) + 28
17  net_unittests                       0x0000000100e75462 base::MessageLoop::DoWork() + 146
18  net_unittests                       0x0000000100e3f42a base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) + 106
19  net_unittests                       0x0000000100e74f5e base::MessageLoop::RunHandler() + 158
20  net_unittests                       0x0000000100e953b3 base::RunLoop::Run() + 51
21  net_unittests                       0x0000000100e954bd base::RunLoop::RunUntilIdle() + 13
22  net_unittests                       0x0000000100e74711 base::MessageLoop::RunUntilIdle() + 113
23  net_unittests                       0x00000001004ad776 net::HttpNetworkTransactionTest::SetUp() + 22
24  net_unittests                       0x0000000100f2d837 void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) + 23
25  net_unittests                       0x0000000100f278e9 void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) + 57
26  net_unittests                       0x0000000100f20566 testing::Test::Run() + 70
27  net_unittests                       0x0000000100f20ab3 testing::TestInfo::Run() + 163
28  net_unittests                       0x0000000100f20e52 testing::TestCase::Run() + 178
29  net_unittests                       0x0000000100f24733 testing::internal::UnitTestImpl::RunAllTests() + 499
30  net_unittests                       0x0000000100f2e897 bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) + 23
31  net_unittests                       0x0000000100f28619 bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) + 57
32  net_unittests                       0x0000000100f24523 testing::UnitTest::Run() + 115
33  net_unittests                       0x0000000101649281 RUN_ALL_TESTS() + 17
34  net_unittests                       0x0000000101648852 base::TestSuite::Run() + 98
35  net_unittests                       0x0000000100c9509c base::internal::RunnableAdapter<int (base::TestSuite::*)()>::Run(base::TestSuite*) + 28
36  net_unittests                       0x0000000100c95049 _ZN4base8internal12InvokeHelperILb0EiNS0_15RunnableAdapterIMNS_9TestSuiteEFivEEENS0_8TypeListIJP12NetTestSuiteEEEE8MakeItSoES6_S9_ + 41
37  net_unittests                       0x0000000100c9500e _ZN4base8internal7InvokerINS_13IndexSequenceIJLm0EEEENS0_9BindStateINS0_15RunnableAdapterIMNS_9TestSuiteEFivEEEFiPS6_ENS0_8TypeListIJNS0_17UnretainedWrapperI12NetTestSuiteEEEEEEENSC_IJNS0_12UnwrapTraitsISF_EEEEENS0_12InvokeHelperILb0EiS9_NSC_IJPSE_EEEEEFivEE3RunEPNS0_13BindStateBaseE + 46
38  net_unittests                       0x00000001010e4fb4 base::Callback<int ()()>::Run() const + 20
39  net_unittests                       0x0000000101640c78 base::(anonymous namespace)::LaunchUnitTestsInternal(base::Callback<int ()()> const&, int, bool, base::Callback<void ()()> const&) + 264
40  net_unittests                       0x0000000101640b53 base::LaunchUnitTests(int, char**, base::Callback<int ()()> const&) + 83
41  net_unittests                       0x0000000100c94d6b main + 123
42  net_unittests                       0x0000000100001674 start + 52
43  ???                                 0x0000000000000005 0x0 + 5

Original issue's description:
> Remove reference counting from HttpNetworkSession.
>
> This makes lifetime cleaner, and helps us avoid the case
> where an HttpNetworkSession outlives the components it points
> to.
>
> Also remove some weird uses a null NetLog in GCM.
>
> TBR=sgurun@chromium.org,davidben@chromium.org,droger@chromium.org
> BUG=515947
>
> Committed: https://crrev.com/468be2ff331c13b1a081d10a3c17e5366d26e577
> Cr-Commit-Position: refs/heads/master@{#348483}

TBR=pauljensen@chromium.org,zea@chromium.org,sgurun@chromium.org,davidben@chromium.org,droger@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=515947
Committed: https://crrev.com/6b3af6e07d19ebb3f86df612ee5a08c8dc8f78ab
Cr-Commit-Position: refs/heads/master@{#348518}

[mmenke, 2015-09-12 02:03:06]

Created Revert of Remove reference counting from HttpNetworkSession.

[commit-bot: I haz the power, 2015-09-12 02:04:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1342613002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1342613002/1

[commit-bot: I haz the power, 2015-09-12 02:06:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-12 02:07:02]

Patchset 1 (id:??) landed as
https://crrev.com/6b3af6e07d19ebb3f86df612ee5a08c8dc8f78ab
Cr-Commit-Position: refs/heads/master@{#348518}

[commit-bot: I haz the power, 2015-09-23 12:27:40]

Patchset 1 (id:??) landed as
https://crrev.com/6b3af6e07d19ebb3f86df612ee5a08c8dc8f78ab
Cr-Commit-Position: refs/heads/master@{#348518}