Pass QuicInMemoryCache directly instead of using a singleton.

net/tools/quic/quic_simple_server_stream.h

Index: net/tools/quic/quic_simple_server_stream.h
diff --git a/net/tools/quic/quic_simple_server_stream.h b/net/tools/quic/quic_simple_server_stream.h
index 731e32f1d455588ff398e128ccd9f4f3d84583f8..fc23e3b267bf4aff3f221ae28e313c8d87c222bf 100644
--- a/net/tools/quic/quic_simple_server_stream.h
+++ b/net/tools/quic/quic_simple_server_stream.h
@@ -13,6 +13,7 @@
 #include "net/quic/core/quic_protocol.h"
 #include "net/quic/core/quic_spdy_stream.h"
 #include "net/spdy/spdy_framer.h"
+#include "net/tools/quic/quic_in_memory_cache.h"
 
 namespace net {
 
@@ -25,7 +26,9 @@ class QuicSimpleServerStreamPeer;
 // response.
 class QuicSimpleServerStream : public QuicSpdyStream {
  public:
-  QuicSimpleServerStream(QuicStreamId id, QuicSpdySession* session);
+  QuicSimpleServerStream(QuicStreamId id,
+                         QuicSpdySession* session,
+                         QuicInMemoryCache* in_memory_cache);
   ~QuicSimpleServerStream() override;
 
   // QuicSpdyStream
@@ -80,6 +83,8 @@ class QuicSimpleServerStream : public QuicSpdyStream {
   int64_t content_length_;
   std::string body_;
 
+  QuicInMemoryCache* in_memory_cache_;  // Not owned.
+
   DISALLOW_COPY_AND_ASSIGN(QuicSimpleServerStream);
 };