AlternativeServiceServers - Added couple of histograms to measure if

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 <algorithm>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/values.h"
 
 namespace net {
 
 namespace {
@@ skipping 26 matching lines @@
     return;
   // Add the entries from persisted data.
   for (std::vector<std::string>::reverse_iterator it = spdy_servers->rbegin();
        it != spdy_servers->rend(); ++it) {
     spdy_servers_map_.Put(*it, support_spdy);
   }
 }
 
 void HttpServerPropertiesImpl::InitializeAlternativeServiceServers(
     AlternativeServiceMap* alternative_service_map) {
+  int32 size_diff =
+      alternative_service_map->size() - alternative_service_map_.size();
+  if (size_diff > 0) {
+    UMA_HISTOGRAM_COUNTS("Net.AlternativeServiceServers.MorePrefsEntries",
+                         size_diff);
+  } else {

[Alexei Svitkine (slow), 2015/12/18 19:58:48]

Should you check that size_diff isn't 0? It's fine to log it for 0 too, but in
that case you should expand the histogram description to mention that case.

[ramant (doing other things), 2015/12/18 21:34:55]

Good point. Changed the histogram name and description.

Done.

+    UMA_HISTOGRAM_COUNTS("Net.AlternativeServiceServers.MoreCacheEntries",
+                         -size_diff);
+  }
+
   // Add the entries from persisted data.
   for (AlternativeServiceMap::reverse_iterator input_it =
            alternative_service_map->rbegin();
        input_it != alternative_service_map->rend(); ++input_it) {
     DCHECK(!input_it->second.empty());
     alternative_service_map_.Put(input_it->first, input_it->second);
   }
 
   // Attempt to find canonical servers.
   uint16 canonical_ports[] = { 80, 443 };
@@ skipping 649 matching lines @@
   base::TimeDelta delay = when > now ? when - now : base::TimeDelta();
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE,
       base::Bind(
           &HttpServerPropertiesImpl::ExpireBrokenAlternateProtocolMappings,
           weak_ptr_factory_.GetWeakPtr()),
       delay);
 }
 
 }  // namespace net