Support server categories in NTPSnippetsService.

components/ntp_snippets/ntp_snippets_fetcher.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 "components/ntp_snippets/ntp_snippets_fetcher.h"
 
 #include <stdlib.h>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 633 matching lines @@
   // Don't record FetchTimes if the result indicates that a precondition
   // failed and we never actually sent a network request
   if (!IsFetchPreconditionFailed(result)) {
     UMA_HISTOGRAM_TIMES("NewTabPage.Snippets.FetchTime",
                         tick_clock_->NowTicks() - fetch_start_time_);
   }
   UMA_HISTOGRAM_ENUMERATION("NewTabPage.Snippets.FetchResult",
                             static_cast<int>(result),
                             static_cast<int>(FetchResult::RESULT_MAX));
 
+  DVLOG(1) << "Fetch finished: " << last_status_;
   if (!snippets_available_callback_.is_null())
     snippets_available_callback_.Run(std::move(snippets));
 }
 
 }  // namespace ntp_snippets