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

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 8a63042988fa7217dd790dd4457820188df81dbe..6520016878137c54af0b399edc92118bdb962156 100644
--- a/chrome/browser/android/offline_pages/prerendering_offliner.cc
+++ b/chrome/browser/android/offline_pages/prerendering_offliner.cc
@@ -294,6 +294,13 @@ bool PrerenderingOffliner::HandleTimeout(int64_t request_id) {
   return false;
 }
 
+void PrerenderingOffliner::ObserveResourceTracking(const ResourceDataType type,
+                                                   int64_t started_count,
+                                                   int64_t completed_count) {
+  // Add the signal to extra data, and use for tracking.
+  loader_->ObserveResourceTracking(type, started_count, completed_count);
+}
+
 void PrerenderingOffliner::SetLoaderForTesting(
     std::unique_ptr<PrerenderingLoader> loader) {
   DCHECK(!loader_);