[Offline pages] Update background loader to override the WebContentsObserver methods expected

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 183 matching lines @@
   ResetState();
   callback.Run(request_id);
 }
 
 bool BackgroundLoaderOffliner::HandleTimeout(const SavePageRequest& request) {
   // TODO(romax): Decide if we want to also take a snapshot on the last timeout
   // for the background loader offliner. crbug.com/705090
   return false;
 }
 
-void BackgroundLoaderOffliner::DocumentLoadedInFrame(
-    content::RenderFrameHost* render_host) {
-  // Inform snapshot controller if in main frame.
-  if (!render_host->GetParent())
-    snapshot_controller_->DocumentAvailableInMainFrame();
+void BackgroundLoaderOffliner::DocumentAvailableInMainFrame() {
+  snapshot_controller_->DocumentAvailableInMainFrame();
 }
 
-void BackgroundLoaderOffliner::DidStopLoading() {
+void BackgroundLoaderOffliner::DocumentOnLoadCompletedInMainFrame() {
   if (!pending_request_.get()) {
     DVLOG(1) << "DidStopLoading called even though no pending request.";
     return;
   }
 
   snapshot_controller_->DocumentOnLoadCompletedInMainFrame();
 }
 
 void BackgroundLoaderOffliner::RenderProcessGone(
     base::TerminationStatus status) {
@@ skipping 197 matching lines @@
     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
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(offline_pages::OfflinerData);