Pass QuicInMemoryCache directly instead of using a singleton.

net/quic/test_tools/mock_quic_dispatcher.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/test_tools/mock_quic_dispatcher.h"
 
 #include "net/quic/test_tools/quic_test_utils.h"
 
 namespace net {
 namespace test {
 
 MockQuicDispatcher::MockQuicDispatcher(
     const QuicConfig& config,
     const QuicCryptoServerConfig* crypto_config,
     QuicVersionManager* version_manager,
     std::unique_ptr<QuicConnectionHelperInterface> helper,
     std::unique_ptr<QuicCryptoServerStream::Helper> session_helper,
-    std::unique_ptr<QuicAlarmFactory> alarm_factory)
+    std::unique_ptr<QuicAlarmFactory> alarm_factory,
+    QuicInMemoryCache* in_memory_cache)
     : QuicSimpleDispatcher(config,
                            crypto_config,
                            version_manager,
                            std::move(helper),
                            std::move(session_helper),
-                           std::move(alarm_factory)) {}
+                           std::move(alarm_factory),
+                           in_memory_cache) {}
 
 MockQuicDispatcher::~MockQuicDispatcher() {}
 
 }  // namespace test
 }  // namespace net