Use webview.request in OAuth scope approval dialog.

chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js

Index: chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js
diff --git a/chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js b/chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js
index 1cce3bfc818728b75b4285082b9301984444a76f..7c23d38a234e328d78dea5f3679154e412f09a93 100644
--- a/chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js
+++ b/chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js
@@ -20,7 +20,7 @@ function loadAuthUrlAndShowWindow(url, win) {
   });
 
   // Request a customized view from GAIA.
-  webview.onBeforeSendHeaders.addListener(function(details) {
+  webview.request.onBeforeSendHeaders.addListener(function(details) {
     headers = details.requestHeaders || [];
     headers.push({'name': 'X-Browser-View',
                   'value': 'embedded'});