Use sockets with unread data if they've never been used before.

net/socket/client_socket_pool_base.cc

Index: net/socket/client_socket_pool_base.cc
diff --git a/net/socket/client_socket_pool_base.cc b/net/socket/client_socket_pool_base.cc
index 1c79923a40057f5db9c2ef2cd9920e4eda4da43e..93bdc92e791bb17e154b2fefe6c047fc213bff69 100644
--- a/net/socket/client_socket_pool_base.cc
+++ b/net/socket/client_socket_pool_base.cc
@@ -449,7 +449,7 @@ bool ClientSocketPoolBaseHelper::AssignIdleSocketToRequest(
   //   the |idle_socket_it| will be set to the newest used idle socket.
   for (std::list<IdleSocket>::iterator it = idle_sockets->begin();
        it != idle_sockets->end();) {
-    if (!it->socket->IsConnectedAndIdle()) {
+    if (!it->IsReusable()) {
       DecrementIdleCount();
       delete it->socket;
       it = idle_sockets->erase(it);
@@ -642,15 +642,19 @@ base::DictionaryValue* ClientSocketPoolBaseHelper::GetInfoAsValue(
   return dict;
 }
 
+bool ClientSocketPoolBaseHelper::IdleSocket::IsReusable() const {
+  if (socket->WasEverUsed())
+    return socket->IsConnectedAndIdle();
+  return socket->IsConnected();
+}
+
 bool ClientSocketPoolBaseHelper::IdleSocket::ShouldCleanup(
     base::TimeTicks now,
     base::TimeDelta timeout) const {
   bool timed_out = (now - start_time) >= timeout;
   if (timed_out)
     return true;
-  if (socket->WasEverUsed())
-    return !socket->IsConnectedAndIdle();
-  return !socket->IsConnected();
+  return !IsReusable();

[mmenke, 2014/02/25 17:01:53]

Hmm...So the old extra check here was useless, given AssignIdleSocketToRequest's
behavior?  The inconsistency was presumably due to a bug fix, which this is
effectively undoing.

Digging through the history gets us all the way back to
https://codereview.chromium.org/21501 (http://crbug.com/4606).  The bug mentions
an SSL socket receiving data when the server is closing a connection.  The
server will, apparently, send the data and wait for a response.  This may mean
this fix is going in the wrong direction.  Should talk to wtc about this.

 }
 
 void ClientSocketPoolBaseHelper::CleanupIdleSockets(bool force) {