[ios] Experimental flag for Pending Index Navigations.

ios/chrome/browser/experimental_flags.h

Index: ios/chrome/browser/experimental_flags.h
diff --git a/ios/chrome/browser/experimental_flags.h b/ios/chrome/browser/experimental_flags.h
index 247635dad1fbe2fa562b0ace6de167ce8a07ac9e..aae2295365921e79d24b95287e68756a5db7c7a7 100644
--- a/ios/chrome/browser/experimental_flags.h
+++ b/ios/chrome/browser/experimental_flags.h
@@ -55,6 +55,9 @@ bool IsSpotlightActionsEnabled();
 // Whether the iOS MDM integration is enabled.
 bool IsMDMIntegrationEnabled();
 
+// Whether the back-forward navigation uses pending index.
+bool IsPendingIndexNavigationEnabled();
+
 }  // namespace experimental_flags
 
 #endif  // IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_