[Offline Pages] Adds UMA for number of started attempts and for network

chrome/browser/android/offline_pages/prerendering_loader.cc

 // Copyright 2016 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/android/offline_pages/prerendering_loader.h"
 
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
+#include "net/base/network_change_notifier.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace offline_pages {
 
 PrerenderingLoader::PrerenderingLoader(content::BrowserContext* browser_context)
     : state_(State::IDLE),
       snapshot_controller_(nullptr),
       browser_context_(browser_context) {
   adapter_.reset(new PrerenderAdapter(this));
 }
@@ skipping 146 matching lines @@
     // Loss of network connection can show up as unsupported scheme per
     // a redirect to a special data URL is used to navigate to error page.
     // We want to be able to retry these request so for now treat any
     // unsupported scheme error as a cancel.
     // TODO(dougarnett): Use new FinalStatus code if/when supported (642768).
     // TODO(dougarnett): Create whitelist of final status codes that should
     // not be considered failures (and define new RequestStatus code for them).
     if (adapter_->GetFinalStatus() ==
         prerender::FinalStatus::FINAL_STATUS_UNSUPPORTED_SCHEME) {
       request_status = Offliner::RequestStatus::PRERENDERING_CANCELED;
+      UMA_HISTOGRAM_ENUMERATION(
+          "OfflinePages.Background.UnsupportedScheme.ConnectionType",
+          net::NetworkChangeNotifier::GetConnectionType(),
+          net::NetworkChangeNotifier::ConnectionType::CONNECTION_LAST + 1);
     }
     adapter_->DestroyActive();
   }
 
   snapshot_controller_.reset(nullptr);
   session_contents_.reset(nullptr);
   state_ = State::IDLE;
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(callback_, request_status, nullptr));
 }
 
 void PrerenderingLoader::CancelPrerender() {
   if (adapter_->IsActive()) {
     adapter_->DestroyActive();
   }
   snapshot_controller_.reset(nullptr);
   session_contents_.reset(nullptr);
   state_ = State::IDLE;
 }
 
 }  // namespace offline_pages