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

chrome/browser/android/offline_pages/prerendering_offliner.h

Index: chrome/browser/android/offline_pages/prerendering_offliner.h
diff --git a/chrome/browser/android/offline_pages/prerendering_offliner.h b/chrome/browser/android/offline_pages/prerendering_offliner.h
index e7a934e4053c5041841af364daf1eb6ff7dc77d1..7224203ee747d10118a268d95ca80627631a9af4 100644
--- a/chrome/browser/android/offline_pages/prerendering_offliner.h
+++ b/chrome/browser/android/offline_pages/prerendering_offliner.h
@@ -39,6 +39,9 @@ class PrerenderingOffliner : public Offliner {
                    const ProgressCallback& progress_callback) override;
   bool Cancel(const CancelCallback& callback) override;
   bool HandleTimeout(int64_t request_id) override;
+  void ObserveResourceTracking(const ResourceDataType type,
+                               int64_t started_count,
+                               int64_t completed_count) override;
 
   // Allows a loader to be injected for testing. This may only be done once
   // and must be called before any of the Offliner interface methods are called.