Mandoline: fix the crash when a remote subframe tries to access session storage.

components/html_viewer/html_widget.cc

Index: components/html_viewer/html_widget.cc
diff --git a/components/html_viewer/html_widget.cc b/components/html_viewer/html_widget.cc
index aacfcacd52b1443f1d788b1af1dcd8f4c0b53755..14c04742564d8d9fb086cf653b1747358683b25d 100644
--- a/components/html_viewer/html_widget.cc
+++ b/components/html_viewer/html_widget.cc
@@ -71,12 +71,21 @@ void ConfigureSettings(blink::WebSettings* settings) {
 // HTMLWidgetRootRemote -------------------------------------------------------
 
 HTMLWidgetRootRemote::HTMLWidgetRootRemote()
-    : web_view_(blink::WebView::create(nullptr)) {
+    : web_view_(blink::WebView::create(this)) {
   ConfigureSettings(web_view_->settings());
 }
 
 HTMLWidgetRootRemote::~HTMLWidgetRootRemote() {}
 
+blink::WebStorageNamespace*
+HTMLWidgetRootRemote::createSessionStorageNamespace() {
+  return new WebStorageNamespaceImpl();
+}
+
+bool HTMLWidgetRootRemote::allowsBrokenNullLayerTreeView() const {
+  return true;
+}
+
 blink::WebWidget* HTMLWidgetRootRemote::GetWidget() {
   return web_view_;
 }