Get signals working in the EXTRA_DATA section of MHTML

chrome/browser/android/offline_pages/offline_page_bridge.cc

 // 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.
 
 #include "chrome/browser/android/offline_pages/offline_page_bridge.h"
 
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 431 matching lines @@
   if (web_contents) {
     save_page_params.url = web_contents->GetLastCommittedURL();
     archiver.reset(new OfflinePageMHTMLArchiver(web_contents));
   }
 
   save_page_params.client_id.name_space =
       ConvertJavaStringToUTF8(env, j_namespace);
   save_page_params.client_id.id = ConvertJavaStringToUTF8(env, j_client_id);
   save_page_params.is_background = false;
 
+  std::string signal_data;
+
   offline_page_model_->SavePage(
-      save_page_params, std::move(archiver),
+      save_page_params, std::move(archiver), signal_data,
       base::Bind(&SavePageCallback, j_callback_ref, save_page_params.url));
 }
 
 void OfflinePageBridge::SavePageLater(JNIEnv* env,
                                       const JavaParamRef<jobject>& obj,
                                       const JavaParamRef<jstring>& j_url,
                                       const JavaParamRef<jstring>& j_namespace,
                                       const JavaParamRef<jstring>& j_client_id,
                                       jboolean user_requested) {
   offline_pages::ClientId client_id;
@@ skipping 167 matching lines @@
       env, ConvertUTF8ToJavaString(env, client_id.name_space),
       ConvertUTF8ToJavaString(env, client_id.id));
 }
 
 bool RegisterOfflinePageBridge(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace android
 }  // namespace offline_pages