Deprecate instead of close SPDY sessions upon network change.

net/spdy/spdy_session_pool.cc

 // 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.
 
 #include "net/spdy/spdy_session_pool.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/values.h"
 #include "net/base/address_list.h"
@@ skipping 260 matching lines @@
     // host_port_proxy_pair (not an alias).
     const SpdySessionKey& key = it->first;
     const SpdySessionKey& session_key = it->second->spdy_session_key();
     if (key.Equals(session_key))
       list->Append(it->second->GetInfoAsValue());
   }
   return list;
 }
 
 void SpdySessionPool::OnIPAddressChanged() {
-  CloseCurrentSessions(ERR_NETWORK_CHANGED);
+  WeakSessionList current_sessions = GetCurrentSessions();
+  for (WeakSessionList::const_iterator it = current_sessions.begin();
+       it != current_sessions.end(); ++it) {
+    if (!*it)
+      continue;
+
+    // For OSs that terminate TCP connections upon relevant network changes
+    // there is no need to explicitly close SpdySessions, instead simply mark
+    // the sessions as deprecated so they aren't reused.
+#if defined(OS_ANDROID) || defined(OS_WIN) || defined(OS_IOS)
+    (*it)->Deprecate();
+#else
+    (*it)->CloseSessionOnError(ERR_NETWORK_CHANGED,
+                               "Closing current sessions.");
+    DCHECK(!*it);
+#endif  // defined(OS_ANDROID) || defined(OS_WIN) || defined(OS_IOS)
+    DCHECK(!IsSessionAvailable(*it));

[akalin, 2014/01/27 22:20:03]

this should probably go in the #if block, since from the #else block *it will be
NULL.

[pauljensen, 2014/01/28 19:34:45]

That was my thought too, but I wanted to keep in line with the style of
SpdySessionPool::CloseCurrentSessionsHelper() where both DCHECKS() are present
and I figured an extra check couldn't hurt and also conveys that either way
through the #if the session won't be available anymore.  Would you like me to
remove the extra DCHECK from SpdySessionPool::CloseCurrentSessionsHelper too?

[akalin, 2014/01/28 23:23:27]

Nevermind I misread the code -- I thought it was a WeakPtr, but it's actually an
iterator that's dereferences to a WeakPtr. It's fine as is!

+  }
   http_server_properties_->ClearAllSpdySettings();
 }
 
 void SpdySessionPool::OnSSLConfigChanged() {
   CloseCurrentSessions(ERR_NETWORK_CHANGED);
 }
 
 void SpdySessionPool::OnCertAdded(const X509Certificate* cert) {
   CloseCurrentSessions(ERR_CERT_DATABASE_CHANGED);
 }
@@ skipping 90 matching lines @@
     if (idle_only && (*it)->is_active())
       continue;
 
     (*it)->CloseSessionOnError(error, description);
     DCHECK(!IsSessionAvailable(*it));
     DCHECK(!*it);
   }
 }
 
 }  // namespace net