Measure browser->render->browser hop time in UMA.

content/browser/loader/async_resource_handler.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 "content/browser/loader/async_resource_handler.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/containers/hash_tables.h"
 #include "base/debug/alias.h"
 #include "base/logging.h"
 #include "base/memory/shared_memory.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/time/time.h"
 #include "content/browser/devtools/devtools_netlog_observer.h"
 #include "content/browser/host_zoom_map_impl.h"
 #include "content/browser/loader/resource_buffer.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_message_filter.h"
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/browser/resource_context_impl.h"
 #include "content/common/resource_messages.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/resource_dispatcher_host_delegate.h"
@@ skipping 79 matching lines @@
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void AsyncResourceHandler::OnFollowRedirect(int request_id) {
   if (!request()->status().is_success()) {
     DVLOG(1) << "OnFollowRedirect for invalid request";
     return;
   }
 
+  if (!redirect_start_time_.is_null()) {
+    UMA_HISTOGRAM_TIMES("Net.AsyncResourceHandler_RedirectHopTime",
+                        TimeTicks::Now() - redirect_start_time_);
+    // Reset start time.
+    redirect_start_time_ = TimeTicks();
+  }
+
   ResumeIfDeferred();
 }
 
 void AsyncResourceHandler::OnDataReceivedACK(int request_id) {
   if (pending_data_count_) {
     --pending_data_count_;
 
     buffer_->RecycleLeastRecentlyAllocated();
     if (buffer_->CanAllocate())
       ResumeIfDeferred();
@@ skipping 10 matching lines @@
 }
 
 bool AsyncResourceHandler::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     ResourceResponse* response,
     bool* defer) {
   const ResourceRequestInfoImpl* info = GetRequestInfo();
   if (!info->filter())
     return false;
 
+  redirect_start_time_ = TimeTicks::Now();
+
   *defer = did_defer_ = true;
   OnDefer();
 
   if (rdh_->delegate()) {
     rdh_->delegate()->OnRequestRedirected(
         redirect_info.new_url, request(), info->GetContext(), response);
   }
 
   DevToolsNetLogObserver::PopulateResponseInfo(request(), response);
   response->head.encoded_data_length = request()->GetTotalReceivedBytes();
@@ skipping 235 matching lines @@
     request()->LogUnblocked();
     controller()->Resume();
   }
 }
 
 void AsyncResourceHandler::OnDefer() {
   request()->LogBlockedBy("AsyncResourceHandler");
 }
 
 }  // namespace content