Get signals working in the EXTRA_DATA section of MHTML

components/offline_pages/core/offline_page_feature.h

Index: components/offline_pages/core/offline_page_feature.h
diff --git a/components/offline_pages/core/offline_page_feature.h b/components/offline_pages/core/offline_page_feature.h
index 9a22029c5033ab7660548da211e5c62750abcd2a..11a5b68cf83a507212c4137072b2a2a55d1b8e81 100644
--- a/components/offline_pages/core/offline_page_feature.h
+++ b/components/offline_pages/core/offline_page_feature.h
@@ -19,6 +19,7 @@ extern const base::Feature kBackgroundLoaderForDownloadsFeature;
 extern const base::Feature kOfflinePagesAsyncDownloadFeature;
 extern const base::Feature kPrefetchingOfflinePagesFeature;
 extern const base::Feature kNewBackgroundLoaderFeature;
+extern const base::Feature kOfflinePagesLoadSignalCollectingFeature;
 
 // Returns true if saving bookmarked pages for offline viewing is enabled.
 bool IsOfflineBookmarksEnabled();
@@ -45,6 +46,9 @@ bool IsOfflinePagesAsyncDownloadEnabled();
 // Returns true if prefetching offline pages is enabled.
 bool IsPrefetchingOfflinePagesEnabled();
 
+// Returns true if we enable load timing signals to be collected.
+bool IsOfflinePagesLoadSignalCollectingEnabled();
+
 // Returns true if we should use background loader rather than prerenderer
 // to offline pages.
 bool ShouldUseNewBackgroundLoader();