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

net/socket/ssl_client_socket_nss.cc

Index: net/socket/ssl_client_socket_nss.cc
diff --git a/net/socket/ssl_client_socket_nss.cc b/net/socket/ssl_client_socket_nss.cc
index 598bb7c154bd02dbe32105ba4098c1034fed2957..624550a1a74a4c1117c8a8c774422927b718461c 100644
--- a/net/socket/ssl_client_socket_nss.cc
+++ b/net/socket/ssl_client_socket_nss.cc
@@ -639,6 +639,7 @@ class SSLClientSocketNSS::Core : public base::RefCountedThreadSafe<Core> {
   bool IsConnected();
   bool HasPendingAsyncOperation();
   bool HasUnhandledReceivedData();
+  bool WasEverUsed();
 
   // Called on the network task runner.
   // Causes the associated SSL/TLS session ID to be added to NSS's session
@@ -840,6 +841,7 @@ class SSLClientSocketNSS::Core : public base::RefCountedThreadSafe<Core> {
   bool nss_waiting_read_;
   bool nss_waiting_write_;
   bool nss_is_closed_;
+  bool was_used_to_convey_data_;

[wtc, 2014/03/19 00:17:46]

Nit: document this member. I copied your comment from _openssl.h:

  // Set when Read() or Write() successfully reads or writes data to or from the
  // network.

[davidben, 2014/03/25 19:50:18]

Done.

 
   ////////////////////////////////////////////////////////////////////////////
   // Members that are ONLY accessed on the NSS task runner:
@@ -936,6 +938,7 @@ SSLClientSocketNSS::Core::Core(
       nss_waiting_read_(false),
       nss_waiting_write_(false),
       nss_is_closed_(false),
+      was_used_to_convey_data_(false),
       host_and_port_(host_and_port),
       ssl_config_(ssl_config),
       nss_fd_(NULL),
@@ -1148,8 +1151,11 @@ int SSLClientSocketNSS::Core::Read(IOBuffer* buf, int buf_len,
       return ERR_IO_PENDING;
     } else {
       DCHECK(!nss_waiting_read_);
-      if (rv <= 0)
+      if (rv <= 0) {
         nss_is_closed_ = true;
+      } else {
+        was_used_to_convey_data_ = true;
+      }
     }
   }
 
@@ -1202,8 +1208,11 @@ int SSLClientSocketNSS::Core::Write(IOBuffer* buf, int buf_len,
       return ERR_IO_PENDING;
     } else {
       DCHECK(!nss_waiting_write_);
-      if (rv < 0)
+      if (rv < 0) {
         nss_is_closed_ = true;
+      } else {

[wtc, 2014/03/19 00:17:46]

We may want to test rv > 0 here because the condition above is not rv <= 0.

[davidben, 2014/03/25 19:50:18]

Done.

+        was_used_to_convey_data_ = true;
+      }
     }
   }
 
@@ -1225,6 +1234,11 @@ bool SSLClientSocketNSS::Core::HasUnhandledReceivedData() {
   return unhandled_buffer_size_ != 0;
 }
 
+bool SSLClientSocketNSS::Core::WasEverUsed() {
+  DCHECK(OnNetworkTaskRunner());
+  return was_used_to_convey_data_;
+}
+
 void SSLClientSocketNSS::Core::CacheSessionIfNecessary() {
   // TODO(rsleevi): This should occur on the NSS task runner, due to the use of
   // nss_fd_. However, it happens on the network task runner in order to match
@@ -2656,16 +2670,22 @@ void SSLClientSocketNSS::Core::DidNSSRead(int result) {
   DCHECK(OnNetworkTaskRunner());
   DCHECK(nss_waiting_read_);
   nss_waiting_read_ = false;
-  if (result <= 0)
+  if (result <= 0) {
     nss_is_closed_ = true;
+  } else {
+    was_used_to_convey_data_ = true;
+  }
 }
 
 void SSLClientSocketNSS::Core::DidNSSWrite(int result) {
   DCHECK(OnNetworkTaskRunner());
   DCHECK(nss_waiting_write_);
   nss_waiting_write_ = false;
-  if (result < 0)
+  if (result < 0) {
     nss_is_closed_ = true;
+  } else {

[wtc, 2014/03/19 00:17:46]

We may want to test rv > 0 here because the condition above is not rv <= 0.

[davidben, 2014/03/25 19:50:18]

Done.

+    was_used_to_convey_data_ = true;
+  }
 }
 
 void SSLClientSocketNSS::Core::BufferSendComplete(int result) {
@@ -3025,11 +3045,9 @@ void SSLClientSocketNSS::SetOmniboxSpeculation() {
 }
 
 bool SSLClientSocketNSS::WasEverUsed() const {
-  if (transport_.get() && transport_->socket()) {
-    return transport_->socket()->WasEverUsed();
-  }
-  NOTREACHED();
-  return false;
+  DCHECK(core_.get());
+
+  return core_->WasEverUsed();
 }
 
 bool SSLClientSocketNSS::UsingTCPFastOpen() const {