Clear SSLClientSessionCache on low memory notifications.

net/ssl/ssl_client_session_cache.cc

Index: net/ssl/ssl_client_session_cache.cc
diff --git a/net/ssl/ssl_client_session_cache.cc b/net/ssl/ssl_client_session_cache.cc
index 82526a5ae4d1a022b0fdbd47c981b592a814cf0a..650d98948a2cacd2093d5fd49faef46fd62a6744 100644
--- a/net/ssl/ssl_client_session_cache.cc
+++ b/net/ssl/ssl_client_session_cache.cc
@@ -15,7 +15,10 @@ SSLClientSessionCache::SSLClientSessionCache(const Config& config)
     : clock_(new base::DefaultClock),
       config_(config),
       cache_(config.max_entries),
-      lookups_since_flush_(0) {}
+      lookups_since_flush_(0) {
+  memory_pressure_listener_.reset(new base::MemoryPressureListener(base::Bind(
+      &SSLClientSessionCache::OnMemoryPressure, base::Unretained(this))));
+}
 
 SSLClientSessionCache::~SSLClientSessionCache() {
   Flush();
@@ -91,4 +94,18 @@ void SSLClientSessionCache::FlushExpiredSessions() {
   }
 }
 
+void SSLClientSessionCache::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  switch (memory_pressure_level) {
+    case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE:
+      break;
+    case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE:
+      FlushExpiredSessions();
+      break;
+    case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL:
+      Flush();
+      break;
+  }
+}
+
 }  // namespace net