Pass QuicInMemoryCache directly instead of using a singleton.

net/tools/quic/quic_simple_server_session.h

Index: net/tools/quic/quic_simple_server_session.h
diff --git a/net/tools/quic/quic_simple_server_session.h b/net/tools/quic/quic_simple_server_session.h
index e075d1be45033d87bf7cc8802f5cac55623c0bc4..8a3f58b786308d2a92690f23e98c6dccc0100e92 100644
--- a/net/tools/quic/quic_simple_server_session.h
+++ b/net/tools/quic/quic_simple_server_session.h
@@ -64,7 +64,8 @@ class QuicSimpleServerSession : public QuicServerSessionBase {
                           QuicSession::Visitor* visitor,
                           QuicCryptoServerStream::Helper* helper,
                           const QuicCryptoServerConfig* crypto_config,
-                          QuicCompressedCertsCache* compressed_certs_cache);
+                          QuicCompressedCertsCache* compressed_certs_cache,
+                          QuicInMemoryCache* in_memory_cache);
 
   ~QuicSimpleServerSession() override;
 
@@ -105,6 +106,8 @@ class QuicSimpleServerSession : public QuicServerSessionBase {
       const QuicCryptoServerConfig* crypto_config,
       QuicCompressedCertsCache* compressed_certs_cache) override;
 
+  QuicInMemoryCache* in_memory_cache() { return in_memory_cache_; }
+
  private:
   friend class test::QuicSimpleServerSessionPeer;
 
@@ -150,6 +153,8 @@ class QuicSimpleServerSession : public QuicServerSessionBase {
   // highest_promised_stream_id_.
   std::deque<PromisedStreamInfo> promised_streams_;
 
+  QuicInMemoryCache* in_memory_cache_;  // Not owned.
+
   DISALLOW_COPY_AND_ASSIGN(QuicSimpleServerSession);
 };