Clear SSLClientSessionCache on low memory notifications.

net/ssl/ssl_client_session_cache.h

Index: net/ssl/ssl_client_session_cache.h
diff --git a/net/ssl/ssl_client_session_cache.h b/net/ssl/ssl_client_session_cache.h
index 149d4dc36d0079dfde3cc630ef6efbbdd9ddb212..63990a9a7c8af7ece8b22d3e301ba59db259580f 100644
--- a/net/ssl/ssl_client_session_cache.h
+++ b/net/ssl/ssl_client_session_cache.h
@@ -11,8 +11,10 @@
 #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"
@@ -74,6 +76,10 @@ class NET_EXPORT SSLClientSessionCache {
   // 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_;
@@ -84,6 +90,8 @@ class NET_EXPORT SSLClientSessionCache {
   // classes in net.
   base::Lock lock_;
 
+  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
+
   DISALLOW_COPY_AND_ASSIGN(SSLClientSessionCache);
 };