Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/browser/frame_host/render_widget_host_view_child_frame.cc

Index: content/browser/frame_host/render_widget_host_view_child_frame.cc
diff --git a/content/browser/frame_host/render_widget_host_view_child_frame.cc b/content/browser/frame_host/render_widget_host_view_child_frame.cc
index 40b54b69ced633e975d5e17b74ec67d2644bc2ad..8a988e7bf7aabe837671a2cd30e9c9ab26254d83 100644
--- a/content/browser/frame_host/render_widget_host_view_child_frame.cc
+++ b/content/browser/frame_host/render_widget_host_view_child_frame.cc
@@ -335,6 +335,12 @@ void RenderWidgetHostViewChildFrame::UnregisterFrameSinkId() {
   }
 }
 
+RenderWidgetHostViewBase*
+RenderWidgetHostViewChildFrame::GetOwnerRenderWidgetHostView() const {
+  NOTREACHED();
+  return nullptr;
+}
+
 void RenderWidgetHostViewChildFrame::GestureEventAck(
     const blink::WebGestureEvent& event,
     InputEventAckState ack_result) {