Turn the flag off and see what happens

content/common/swapped_out_messages.cc

Index: content/common/swapped_out_messages.cc
diff --git a/content/common/swapped_out_messages.cc b/content/common/swapped_out_messages.cc
index 05b5781b9151afc974b80bfbd86df5a6a596f300..47acc358e02733cf7385b46f54dabd8cf4c01e83 100644
--- a/content/common/swapped_out_messages.cc
+++ b/content/common/swapped_out_messages.cc
@@ -5,6 +5,7 @@
 #include "content/common/swapped_out_messages.h"
 
 #include "content/common/accessibility_messages.h"
+#include "content/common/frame_messages.h"
 #include "content/common/input_messages.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/content_client.h"
@@ -35,6 +36,8 @@ bool SwappedOutMessages::CanSendWhileSwappedOut(const IPC::Message* msg) {
     // Allow cross-process JavaScript calls.
     case ViewHostMsg_RouteCloseEvent::ID:
     case ViewHostMsg_RouteMessageEvent::ID:
+    // Frame detach must occur after the RenderView has swapped out.
+    case FrameHostMsg_Detach::ID:
       return true;
     default:
       break;