[Offline Pages] Adding missing image/CSS detection in FrameSerializer.

content/browser/download/mhtml_generation_manager.cc

Index: content/browser/download/mhtml_generation_manager.cc
diff --git a/content/browser/download/mhtml_generation_manager.cc b/content/browser/download/mhtml_generation_manager.cc
index 001d30d59f469fbfc9696f80015393a5d031b473..7cb86e8a45a3dbbb70740c46c4f7113a0c779b1a 100644
--- a/content/browser/download/mhtml_generation_manager.cc
+++ b/content/browser/download/mhtml_generation_manager.cc
@@ -253,6 +253,7 @@ MhtmlSaveStatus MHTMLGenerationManager::Job::SendToNextRenderFrame() {
   ipc_params.mhtml_binary_encoding = params_.use_binary_encoding;
   ipc_params.mhtml_cache_control_policy = params_.cache_control_policy;
   ipc_params.mhtml_popup_overlay_removal = params_.remove_popup_overlay;
+  ipc_params.mhtml_problem_detection = params_.use_page_problem_detectors;
 
   int frame_tree_node_id = pending_frame_tree_node_ids_.front();
   pending_frame_tree_node_ids_.pop();