Use webview.request in OAuth scope approval dialog.

The WebRequest API on webviews moved to a new location.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23493021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221589 0039d316-1c4b-4281-b951-d872f2087c98

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'});