Fix browser launch on the login screen.

ui/web_dialogs/web_dialog_delegate.cc

Index: ui/web_dialogs/web_dialog_delegate.cc
diff --git a/ui/web_dialogs/web_dialog_delegate.cc b/ui/web_dialogs/web_dialog_delegate.cc
index e1191f6382d72ab23cead89b92718783a50eb961..d903f304d40c4b4e3db8bfe4089b2cb1aa4fe94b 100644
--- a/ui/web_dialogs/web_dialog_delegate.cc
+++ b/ui/web_dialogs/web_dialog_delegate.cc
@@ -48,4 +48,16 @@ bool WebDialogDelegate::HandleAddNewContents(
   return false;
 }
 
+bool WebDialogDelegate::HandleShouldCreateWebContents(
+    content::WebContents* web_contents,
+    int route_id,
+    int main_frame_route_id,
+    WindowContainerType window_container_type,
+    const base::string16& frame_name,
+    const GURL& target_url,
+    const std::string& partition_id,
+    content::SessionStorageNamespace* session_storage_namespace) {
+  return true;
+}
+
 }  // namespace ui