Pass QuicInMemoryCache directly instead of using a singleton.

net/quic/test_tools/mock_quic_dispatcher.cc

Index: net/quic/test_tools/mock_quic_dispatcher.cc
diff --git a/net/quic/test_tools/mock_quic_dispatcher.cc b/net/quic/test_tools/mock_quic_dispatcher.cc
index a8add6553c069782aa7d99842c40726943b32e43..efe4a80300cf18346238f22864a6426eb37b8b47 100644
--- a/net/quic/test_tools/mock_quic_dispatcher.cc
+++ b/net/quic/test_tools/mock_quic_dispatcher.cc
@@ -15,13 +15,15 @@ MockQuicDispatcher::MockQuicDispatcher(
     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() {}