Record forced alternative service histogram.

net/http/http_server_properties_impl.cc

 // Copyright (c) 2012 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 "net/http/http_server_properties_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 
 namespace net {
 
 namespace {
 
 const uint64 kBrokenAlternateProtocolDelaySecs = 300;
 
@@ skipping 217 matching lines @@
 }
 
 AlternateProtocolInfo HttpServerPropertiesImpl::GetAlternateProtocol(
     const HostPortPair& server) {
   AlternateProtocolMap::const_iterator it =
       GetAlternateProtocolIterator(server);
   if (it != alternate_protocol_map_.end() &&
       it->second.probability >= alternate_protocol_probability_threshold_)
     return it->second;
 
+  UMA_HISTOGRAM_BOOLEAN("Net.ForceAlternativeService",
+                        g_forced_alternate_protocol != nullptr);
   if (g_forced_alternate_protocol)
     return *g_forced_alternate_protocol;
 
   AlternateProtocolInfo uninitialized_alternate_protocol;
   return uninitialized_alternate_protocol;
 }
 
 void HttpServerPropertiesImpl::SetAlternateProtocol(
     const HostPortPair& server,
     uint16 alternate_port,
@@ skipping 297 matching lines @@
   base::TimeDelta delay = when > now ? when - now : base::TimeDelta();
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(
           &HttpServerPropertiesImpl::ExpireBrokenAlternateProtocolMappings,
           weak_ptr_factory_.GetWeakPtr()),
       delay);
 }
 
 }  // namespace net