Return operation name in prefetch request callback and add internal page hookup

components/offline_pages/core/prefetch/prefetch_types.h

Index: components/offline_pages/core/prefetch/prefetch_types.h
diff --git a/components/offline_pages/core/prefetch/prefetch_types.h b/components/offline_pages/core/prefetch/prefetch_types.h
index 80208f0abe8a5b0931ceb92f90d52aa7a2b4563f..8fb4bbe491c23dc75bfc7ce6aa831feb0e2581cd 100644
--- a/components/offline_pages/core/prefetch/prefetch_types.h
+++ b/components/offline_pages/core/prefetch/prefetch_types.h
@@ -106,6 +106,7 @@ enum class PrefetchItemErrorCode {
 // Callback invoked upon completion of a prefetch request.
 using PrefetchRequestFinishedCallback =
     base::Callback<void(PrefetchRequestStatus status,
+                        const std::string& operation_name,
                         const std::vector<RenderPageInfo>& pages)>;
 
 // Holds information about a new URL to be prefetched.