Resend on IO errors on late bound sockets that were idle.

According to UMA data, late bound sockets that were idle are significantly more likely to get (reset/close/abort) errors.  Currently, we don't resend on late bound sockets that were idle because they weren't reused.  This changes that.
TODO: determine how long a socket has to be idle before it is likely to get a TCP RST if we try to reuse it.
Also document the ClientSocketHandle::ReuseSocketType values.
BUG=http://crbug.com/18192.

Review URL: http://codereview.chromium.org/174287

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@24084 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 5 insertions, 4 deletions

diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index 79be223..d37bab4 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -1554,7 +1554,8 @@ bool HttpNetworkTransaction::ShouldResendRequest() const {
   // This automatically prevents an infinite resend loop because we'll run
   // out of the cached keep-alive connections eventually.
   if (establishing_tunnel_ ||
-      !reused_socket_ ||  // We didn't reuse a keep-alive connection.
+      // We used a socket that was never idle.
+      connection_.reuse_type() == ClientSocketHandle::UNUSED ||
       header_buf_len_) {  // We have received some response headers.
     return false;
   }
diff --git a/net/socket/client_socket_handle.h b/net/socket/client_socket_handle.h
index ce0a001..d323313 100644
--- a/net/socket/client_socket_handle.h
+++ b/net/socket/client_socket_handle.h
@@ -28,9 +28,9 @@ namespace net {
 class ClientSocketHandle {
  public:
   typedef enum {
-    UNUSED = 0,
-    UNUSED_IDLE,
-    REUSED_IDLE,
+    UNUSED = 0,   // unused socket that just finished connectin
+    UNUSED_IDLE,  // unused socket that has been idle for awhile
+    REUSED_IDLE,  // previously used socket
     NUM_TYPES,
   } SocketReuseType;