Add a way to send the resource percentage signal to the RC.

chrome/browser/android/offline_pages/prerendering_loader.h

Index: chrome/browser/android/offline_pages/prerendering_loader.h
diff --git a/chrome/browser/android/offline_pages/prerendering_loader.h b/chrome/browser/android/offline_pages/prerendering_loader.h
index a3ed68cac63de00748494a65e6eca245ac193d46..d4e5de43faaa2555da27cca6083ddcbe79287bae 100644
--- a/chrome/browser/android/offline_pages/prerendering_loader.h
+++ b/chrome/browser/android/offline_pages/prerendering_loader.h
@@ -85,6 +85,10 @@ class PrerenderingLoader : public PrerenderAdapter::Observer,
   // Returns true if the lowbar of snapshotting a page is met.
   virtual bool IsLowbarMet();
 
+  void ObserveResourceTracking(const Offliner::ResourceDataType type,
+                               int64_t started_count,
+                               int64_t completed_count);
+
   // Returns a JSON dictionary value for analysis of loading progress.
   const base::DictionaryValue& GetLoadingSignalData() { return signal_data_; }