Add field trial stats for alternate_protocol.

webkit/glue/resource_loader_bridge.h

Index: webkit/glue/resource_loader_bridge.h
===================================================================
--- webkit/glue/resource_loader_bridge.h	(revision 50874)
+++ webkit/glue/resource_loader_bridge.h	(working copy)
@@ -128,6 +128,10 @@
     // True if the response was delivered after NPN is negotiated.
     bool was_npn_negotiated;
 
+    // True if response could use alternate protocol. However, browser will
+    // ignore the alternate protocol when spdy is not enabled on browser side.
+    bool was_alternate_protocol_available;
+
     // True if the response was fetched via an explicit proxy (as opposed to a
     // transparent proxy). The proxy could be any type of proxy, HTTP or SOCKS.
     // Note: we cannot tell if a transparent proxy may have been involved.