Add --use-more-webui runtime flag to toggle WebUI replacements for native dialogs.

chrome/browser/certificate_viewer.h

Index: chrome/browser/certificate_viewer.h
diff --git a/chrome/browser/certificate_viewer.h b/chrome/browser/certificate_viewer.h
index 89b0e04bbcd91da0c819da5e2d36770d3abff7e6..f80004f4a43b1ea677698007e55b16f380645dde 100644
--- a/chrome/browser/certificate_viewer.h
+++ b/chrome/browser/certificate_viewer.h
@@ -22,4 +22,9 @@ void ShowCertificateViewerByID(gfx::NativeWindow parent, int cert_id);
 void ShowCertificateViewer(gfx::NativeWindow parent,
                            net::X509Certificate* cert);
 
+// Opens a certificate viewer under |parent| to display |cert| using a native
+// certificate viewer dialog.
+void ShowNativeCertificateViewer(gfx::NativeWindow parent,
+                                 net::X509Certificate* cert);
+
 #endif  // CHROME_BROWSER_CERTIFICATE_VIEWER_H_