Get signals working in the EXTRA_DATA section of MHTML

chrome/browser/android/offline_pages/prerendering_loader.cc

Index: chrome/browser/android/offline_pages/prerendering_loader.cc
diff --git a/chrome/browser/android/offline_pages/prerendering_loader.cc b/chrome/browser/android/offline_pages/prerendering_loader.cc
index 0b2f878764963cadf74a4cf1ec95240527f95c2f..350ed8c110daa9d4183aa724825e83f887ff5a4e 100644
--- a/chrome/browser/android/offline_pages/prerendering_loader.cc
+++ b/chrome/browser/android/offline_pages/prerendering_loader.cc
@@ -152,6 +152,9 @@ void PrerenderingLoader::OnPrerenderStopLoading() {
   // Inform SnapshotController of OnLoad event so it can determine
   // when to consider it really LOADED.
   snapshot_controller_->DocumentOnLoadCompletedInMainFrame();
+
+  // Add this signal to signal_data_.
+  signal_data_.push_back(std::string("OnLoad signal seen"));
 }
 
 void PrerenderingLoader::OnPrerenderDomContentLoaded() {
@@ -168,6 +171,9 @@ void PrerenderingLoader::OnPrerenderDomContentLoaded() {
       // second delay from this event).
       snapshot_controller_->DocumentAvailableInMainFrame();
     }
+
+    // Add this signal to signal_data_.
+    signal_data_.push_back(std::string("Dom Content Loaded signal seen"));
   }
 }