Clear SSLClientSessionCache on low memory notifications.

net/ssl/ssl_client_session_cache.h

 // Copyright 2015 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_SSL_SSL_CLIENT_SESSION_CACHE_H
 #define NET_SSL_SSL_CLIENT_SESSION_CACHE_H
 
 #include <openssl/ssl.h>
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 
+#include "base/bind.h"
 #include "base/containers/mru_cache.h"
 #include "base/macros.h"
+#include "base/memory/memory_pressure_monitor.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "net/base/net_export.h"
 #include "net/ssl/scoped_openssl_types.h"
 
 namespace base {
 class Clock;
 }
 
@@ skipping 41 matching lines @@
 
   using CacheEntryMap =
       base::HashingMRUCache<std::string, std::unique_ptr<CacheEntry>>;
 
   // Returns true if |entry| is expired as of |now|.
   bool IsExpired(CacheEntry* entry, const base::Time& now);
 
   // Removes all expired sessions from the cache.
   void FlushExpiredSessions();
 
+  // Clear cache on low memory notifications callback.
+  void OnMemoryPressure(
+      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
+
   std::unique_ptr<base::Clock> clock_;
   Config config_;
   CacheEntryMap cache_;
   size_t lookups_since_flush_;
 
   // TODO(davidben): After https://crbug.com/458365 is fixed, replace this with
   // a ThreadChecker. The session cache should be single-threaded like other
   // classes in net.
   base::Lock lock_;
 
+  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
+
   DISALLOW_COPY_AND_ASSIGN(SSLClientSessionCache);
 };
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_CLIENT_SESSION_CACHE_H