[NTP Snippets] Add UMA for database load time

components/ntp_snippets/remote/ntp_snippets_service.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_SERVICE_H_
 
 #include <cstddef>
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "components/image_fetcher/image_fetcher_delegate.h"
 #include "components/ntp_snippets/category.h"
 #include "components/ntp_snippets/category_factory.h"
 #include "components/ntp_snippets/category_status.h"
 #include "components/ntp_snippets/content_suggestion.h"
 #include "components/ntp_snippets/content_suggestions_provider.h"
 #include "components/ntp_snippets/remote/ntp_snippet.h"
 #include "components/ntp_snippets/remote/ntp_snippets_fetcher.h"
 #include "components/ntp_snippets/remote/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/remote/ntp_snippets_status_service.h"
@@ skipping 307 matching lines @@
   NTPSnippetsScheduler* scheduler_;
 
   // The snippets fetcher.
   std::unique_ptr<NTPSnippetsFetcher> snippets_fetcher_;
 
   std::unique_ptr<image_fetcher::ImageFetcher> image_fetcher_;
   std::unique_ptr<image_fetcher::ImageDecoder> image_decoder_;
 
   // The database for persisting snippets.
   std::unique_ptr<NTPSnippetsDatabase> database_;
+  base::TimeTicks database_load_start_;
 
   // The service that provides events and data about the signin and sync state.
   std::unique_ptr<NTPSnippetsStatusService> snippets_status_service_;
 
   // Set to true if FetchSnippets is called while the service isn't ready.
   // The fetch will be executed once the service enters the READY state.
   bool fetch_when_ready_;
 
   // Set to true if NukeAllSnippets is called while the service isn't ready.
   // The nuke will be executed once the service finishes initialization or
   // enters the READY state.
   bool nuke_when_initialized_;
 
   // Request throttler for limiting requests to thumbnail images.
   RequestThrottler thumbnail_requests_throttler_;
 
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsService);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_SERVICE_H_