Get signals working in the EXTRA_DATA section of MHTML

chrome/browser/android/offline_pages/prerendering_offliner.cc

Index: chrome/browser/android/offline_pages/prerendering_offliner.cc
diff --git a/chrome/browser/android/offline_pages/prerendering_offliner.cc b/chrome/browser/android/offline_pages/prerendering_offliner.cc
index a6564ad078d662af7b164c009e039d8dd89aa383..b5ca6b2089ca84176811c4b01285423facb01122 100644
--- a/chrome/browser/android/offline_pages/prerendering_offliner.cc
+++ b/chrome/browser/android/offline_pages/prerendering_offliner.cc
@@ -83,7 +83,17 @@ void PrerenderingOffliner::OnLoadPageDone(
     else if (save_page_params.url != request.url())
       save_page_params.original_url = request.url();
 
-    SavePage(save_page_params, std::move(archiver),
+    // Write the signal data into a single string.
+    std::string signal_string;
+    const std::vector<std::string>& signals = loader_->GetSignalData();
+
+    // TODO(petewil): Convert this to JSON.
+    for (std::string signal : signals) {
+      signal_string += signal;
+      signal_string += "\r\f";
+    }
+
+    SavePage(save_page_params, std::move(archiver), signal_string,
              base::Bind(&PrerenderingOffliner::OnSavePageDone,
                         weak_ptr_factory_.GetWeakPtr(), request));
   } else {
@@ -253,10 +263,11 @@ void PrerenderingOffliner::SetApplicationStateForTesting(
 void PrerenderingOffliner::SavePage(
     const OfflinePageModel::SavePageParams& save_page_params,
     std::unique_ptr<OfflinePageArchiver> archiver,
+    const std::string& signal_data,
     const SavePageCallback& save_callback) {
   DCHECK(offline_page_model_);
-  offline_page_model_->SavePage(
-      save_page_params, std::move(archiver), save_callback);
+  offline_page_model_->SavePage(save_page_params, std::move(archiver),
+                                signal_data, save_callback);
 }
 
 PrerenderingLoader* PrerenderingOffliner::GetOrCreateLoader() {