Get signals working in the EXTRA_DATA section of MHTML

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 6bcea32cfa26142cb38e8e30f3695e83802fd1ce..47f2550755ee7e190fe8e929d2347d55fb16104a 100644
--- a/content/browser/download/mhtml_generation_manager.cc
+++ b/content/browser/download/mhtml_generation_manager.cc
@@ -232,6 +232,11 @@ MhtmlSaveStatus MHTMLGenerationManager::Job::SendToNextRenderFrame() {
       browser_file_.GetPlatformFile(), false);  // |close_source_handle|.
   ipc_params.frame_routing_id_to_content_id =
       CreateFrameRoutingIdToContentId(rfh->GetSiteInstance());
+  if (params_.extra_data.size() > 0) {
+    // TODO(petewil): only need this on the main frame. How do I check which
+    // frame this is?
+    ipc_params.extra_data = params_.extra_data;

[fgorski, 2017/02/07 22:06:08]

do we really want to pass the data over IPC?
Did you consider appending to the file when it is already written?

(This implies handling the file size appropriately as well)

+  }
 
   // Send the IPC asking the renderer to serialize the frame.
   DCHECK_EQ(FrameTreeNode::kFrameTreeNodeInvalidId,