Deprecate instead of close SPDY sessions upon network change.

net/spdy/spdy_session_pool.cc

Index: net/spdy/spdy_session_pool.cc
diff --git a/net/spdy/spdy_session_pool.cc b/net/spdy/spdy_session_pool.cc
index 72beec465db4a1e2e110f2e34d98423375a10d0c..b34bb96c24f7ee1ecc14bb4f901c2c164b7cbc2e 100644
--- a/net/spdy/spdy_session_pool.cc
+++ b/net/spdy/spdy_session_pool.cc
@@ -278,7 +278,24 @@ base::Value* SpdySessionPool::SpdySessionPoolInfoToValue() const {
 }
 
 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();
 }