Introduce new SPDY Version UMA histogram.

net/socket/next_proto.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "next_proto.h"
+#include "net/socket/next_proto.h"
+
+#include "base/logging.h"
 
 namespace net {
 
+unsigned int SpdyProtoPermanentValue(NextProto protocol) {
+  // These values are collected by UMA, do not change or reuse them.  When
+  // adding new values, do not forget to update spdyProtoPermanentValueBoundary.
+  switch (protocol) {
+    case kProtoDeprecatedSPDY2:
+      return 1;
+    case kProtoSPDY3:
+      return 2;
+    case kProtoSPDY31:
+      return 3;
+    // SPDY4 currently is HTTP/2 draft-14.
+    // TODO(bnc): increment when we update to new draft or final specification.
+    case kProtoSPDY4:
+      return 4;
+    default:
+      NOTREACHED() << "Invalid SPDY protocol.";
+      return 0;
+  }
+}
+
 NextProtoVector NextProtosHttpOnly() {
   NextProtoVector next_protos;
   next_protos.push_back(kProtoHTTP11);
   return next_protos;
 }
 
 NextProtoVector NextProtosDefaults() {
   NextProtoVector next_protos;
   next_protos.push_back(kProtoHTTP11);
   next_protos.push_back(kProtoSPDY3);
@@ skipping 45 matching lines @@
   NextProtoVector next_protos;
   next_protos.push_back(kProtoHTTP11);
   next_protos.push_back(kProtoQUIC1SPDY3);
   next_protos.push_back(kProtoSPDY3);
   next_protos.push_back(kProtoSPDY31);
   next_protos.push_back(kProtoSPDY4);
   return next_protos;
 }
 
 }  // namespace net