Enable forced extension updates on NaCl arch mismatch.

chrome/browser/extensions/updater/extension_downloader.h

Index: chrome/browser/extensions/updater/extension_downloader.h
diff --git a/chrome/browser/extensions/updater/extension_downloader.h b/chrome/browser/extensions/updater/extension_downloader.h
index a0409866f17938dfcfb8bd9594de7fe2cfbce0b9..813a400df11024df8dd6b5f4d2a64737a218d565 100644
--- a/chrome/browser/extensions/updater/extension_downloader.h
+++ b/chrome/browser/extensions/updater/extension_downloader.h
@@ -166,7 +166,9 @@ class ExtensionDownloader
                         Manifest::Type extension_type,
                         const GURL& extension_update_url,
                         const std::string& update_url_data,
-                        int request_id);
+                        int request_id,
+                        bool force_update,
+                        const std::string& install_source_override);
 
   // Adds all recorded stats taken so far to histogram counts.
   void ReportStats() const;