Reland 54771 (and 54795) To enable TCP Preconnection by default

I pulled out the code to update the socket connectivity stats.

I added defensive code which should preclude the crash that 
was reported on the stability bot.

I added a second call to update the stats from
~ClientSocketHandle to ensure that we updated the
related ClientSocket when we are torn down.

As noted in the original checkin:

Enable speculative preconnection by default

Added histogram to track preconnection utilization (vs waste).

BUG=42694
r=mbelshe
Review URL: http://codereview.chromium.org/3050040

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55197 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 13 insertions, 1 deletions

diff --git a/net/socket/client_socket_handle.h b/net/socket/client_socket_handle.h
index adccc89..a3de0d6 100644
--- a/net/socket/client_socket_handle.h
+++ b/net/socket/client_socket_handle.h
@@ -132,7 +132,10 @@ class ClientSocketHandle {
   const std::string& group_name() const { return group_name_; }
   int id() const { return pool_id_; }
   ClientSocket* socket() { return socket_.get(); }
-  ClientSocket* release_socket() { return socket_.release(); }
+  ClientSocket* release_socket() {
+    UpdateConnectivityStateForSocket();
+    return socket_.release();
+  }
   bool is_reused() const { return is_reused_; }
   base::TimeDelta idle_time() const { return idle_time_; }
   SocketReuseType reuse_type() const {
@@ -174,6 +177,15 @@ class ClientSocketHandle {
   // Resets the supplemental error state.
   void ResetErrorState();
 
+  // Update the base class to record things like whether we've ever transmitted
+  // data, and whether the connection was able to be established.  We use this
+  // data to construct histograms indicating whether a speculative connection
+  // was ever used, etc., when the ClientSocket is eventually discarded.
+  void UpdateConnectivityStateForSocket() const {
+    if (socket_.get())
+      socket_->UpdateConnectivityState(is_reused());
+  }
+
   bool is_initialized_;
   scoped_refptr<ClientSocketPool> pool_;
   scoped_ptr<ClientSocket> socket_;