Get signals working in the EXTRA_DATA section of MHTML

chrome/browser/android/offline_pages/background_loader_offliner.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/background_loader_offliner.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/sys_info.h"
 #include "chrome/browser/android/offline_pages/offline_page_mhtml_archiver.h"
 #include "chrome/browser/android/offline_pages/offliner_helper.h"
@@ skipping 282 matching lines @@
   params.proposed_offline_id = request.request_id();
   params.is_background = true;
 
   // Pass in the original URL if it's different from last committed
   // when redirects occur.
   if (!request.original_url().is_empty())
     params.original_url = request.original_url();
   else if (params.url != request.url())
     params.original_url = request.url();
 
+  // TODO(petewil): Generate signal data.  Blank for now.
+  std::string signal_data;
+
   offline_page_model_->SavePage(
-      params, std::move(archiver),
+      params, std::move(archiver), signal_data,
       base::Bind(&BackgroundLoaderOffliner::OnPageSaved,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 void BackgroundLoaderOffliner::OnPageSaved(SavePageResult save_result,
                                            int64_t offline_id) {
   if (!pending_request_)
     return;
 
   SavePageRequest request(*pending_request_.get());
@@ skipping 47 matching lines @@
 void BackgroundLoaderOffliner::HandleApplicationStateChangeCancel(
     const SavePageRequest& request,
     int64_t offline_id) {
   // If for some reason the request was reset during while waiting for callback
   // ignore the completion callback.
   if (pending_request_ && pending_request_->request_id() != offline_id)
     return;
   completion_callback_.Run(request, RequestStatus::FOREGROUND_CANCELED);
 }
 }  // namespace offline_pages