Add UMA to determine how often we offline a page with previews.

chrome/browser/loader/chrome_resource_dispatcher_host_delegate.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 "chrome/browser/loader/chrome_resource_dispatcher_host_delegate.h"
 
 #include <stdint.h>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 53 matching lines @@
 #include "content/public/browser/plugin_service_filter.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_context.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/service_worker_context.h"
 #include "content/public/browser/stream_info.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/previews_state.h"
 #include "content/public/common/resource_response.h"
 #include "extensions/features/features.h"
 #include "net/base/load_flags.h"
 #include "net/base/load_timing_info.h"
 #include "net/base/request_priority.h"
 #include "net/http/http_response_headers.h"
 #include "net/ssl/client_cert_store.h"
 #include "net/url_request/url_request.h"
 #include "third_party/protobuf/src/google/protobuf/repeated_field.h"
 
@@ skipping 844 matching lines @@
 }
 
 content::NavigationData*
 ChromeResourceDispatcherHostDelegate::GetNavigationData(
     net::URLRequest* request) const {
   ChromeNavigationData* data =
       ChromeNavigationData::GetDataAndCreateIfNecessary(request);
   if (!request)
     return data;
 
+  // Update the previews state from the navigation data.
+  const content::ResourceRequestInfo* info =
+      content::ResourceRequestInfo::ForRequest(request);
+  if (info) {
+    data->set_previews_state(info->GetPreviewsState());
+  }
+
   data_reduction_proxy::DataReductionProxyData* data_reduction_proxy_data =
       data_reduction_proxy::DataReductionProxyData::GetData(*request);
   // DeepCopy the DataReductionProxyData from the URLRequest to prevent the
   // URLRequest and DataReductionProxyData from both having ownership of the
   // same object. This copy will be shortlived as it will be deep copied again
   // when content makes a clone of NavigationData for the UI thread.
   if (data_reduction_proxy_data)
     data->SetDataReductionProxyData(data_reduction_proxy_data->DeepCopy());
   return data;
 }
@@ skipping 17 matching lines @@
             &ChromeResourceDispatcherHostDelegate::OnAbortedFrameLoad,
             base::Unretained(this), url, request_loading_time));
     return;
   }
 
   std::string metric_name = (request_loading_time.InMilliseconds() < 100 ?
       "Net.ErrAborted.Fast" : "Net.ErrAborted.Slow");
   rappor::SampleDomainAndRegistryFromGURL(
       g_browser_process->rappor_service(), metric_name, url);
 }