[HttpNetworkSession] Flush socket pools on low memory notification.

net/http/http_network_session.h

 // Copyright (c) 2012 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.
 
 #ifndef NET_HTTP_HTTP_NETWORK_SESSION_H_
 #define NET_HTTP_HTTP_NETWORK_SESSION_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <set>
 #include <string>
 #include <unordered_set>
 #include <vector>
 
+#include "base/bind.h"
+#include "base/memory/memory_pressure_monitor.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/net_export.h"
 #include "net/dns/host_resolver.h"
 #include "net/http/http_auth_cache.h"
 #include "net/http/http_stream_factory.h"
 #include "net/quic/quic_stream_factory.h"
 #include "net/socket/next_proto.h"
@@ skipping 239 matching lines @@
   // |request|.
   void GetSSLConfig(const HttpRequestInfo& request,
                     SSLConfig* server_config,
                     SSLConfig* proxy_config) const;
 
  private:
   friend class HttpNetworkSessionPeer;
 
   ClientSocketPoolManager* GetSocketPoolManager(SocketPoolType pool_type);
 
+  // Flush sockets on low memory notifications callback.
+  void OnMemoryPressure(
+      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
+
   NetLog* const net_log_;
   HttpServerProperties* const http_server_properties_;
   CertVerifier* const cert_verifier_;
   HttpAuthHandlerFactory* const http_auth_handler_factory_;
 
   // Not const since it's modified by HttpNetworkSessionPeer for testing.
   ProxyService* proxy_service_;
   const scoped_refptr<SSLConfigService> ssl_config_service_;
 
   HttpAuthCache http_auth_cache_;
   SSLClientAuthCache ssl_client_auth_cache_;
   std::unique_ptr<ClientSocketPoolManager> normal_socket_pool_manager_;
   std::unique_ptr<ClientSocketPoolManager> websocket_socket_pool_manager_;
   QuicStreamFactory quic_stream_factory_;
   SpdySessionPool spdy_session_pool_;
   std::unique_ptr<HttpStreamFactory> http_stream_factory_;
   std::unique_ptr<HttpStreamFactory> http_stream_factory_for_websocket_;
   std::set<HttpResponseBodyDrainer*> response_drainers_;
 
   NextProtoVector next_protos_;
   bool enabled_protocols_[NUM_VALID_ALTERNATE_PROTOCOLS];
 
   Params params_;
+
+  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_NETWORK_SESSION_H_