permissionrequest API for guest Download.

content/public/browser/web_contents_delegate.cc

Index: content/public/browser/web_contents_delegate.cc
diff --git a/content/public/browser/web_contents_delegate.cc b/content/public/browser/web_contents_delegate.cc
index 7a4409d1e15d8db5a95b0912da3523f3ed38cfbb..db56c7e2d06bc4b5443da6049a18047388697105 100644
--- a/content/public/browser/web_contents_delegate.cc
+++ b/content/public/browser/web_contents_delegate.cc
@@ -69,10 +69,12 @@ int WebContentsDelegate::GetExtraRenderViewHeight() const {
   return 0;
 }
 
-bool WebContentsDelegate::CanDownload(RenderViewHost* render_view_host,
-                                      int request_id,
-                                      const std::string& request_method) {
-  return true;
+void WebContentsDelegate::CanDownload(
+    RenderViewHost* render_view_host,
+    int request_id,
+    const std::string& request_method,
+    const base::Callback<void(bool)>& callback) {
+  callback.Run(true);
 }
 
 bool WebContentsDelegate::HandleContextMenu(