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..ed5586cc07d8fe68ffbf19acadd589af9be73b9f 100644
--- a/chrome/browser/android/offline_pages/prerendering_offliner.h
+++ b/chrome/browser/android/offline_pages/prerendering_offliner.h
@@ -11,6 +11,7 @@
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/android/offline_pages/prerendering_loader.h"
 #include "components/offline_pages/core/background/offliner.h"
+#include "components/offline_pages/core/background/resource_data_type.h"
 #include "components/offline_pages/core/offline_page_model.h"
 #include "components/offline_pages/core/offline_page_types.h"
 
@@ -39,6 +40,9 @@ 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.