WebUI: Fix lifecycle-bug when RenderFrameHost is swapped out

content/public/browser/web_ui_message_handler.h

Index: content/public/browser/web_ui_message_handler.h
diff --git a/content/public/browser/web_ui_message_handler.h b/content/public/browser/web_ui_message_handler.h
index ed0117931f59bc8cc8db1b135a2c606aea0c2015..50da276ef83fcf1760ec49f6b80866b2c0a9c9aa 100644
--- a/content/public/browser/web_ui_message_handler.h
+++ b/content/public/browser/web_ui_message_handler.h
@@ -106,6 +106,9 @@ class CONTENT_EXPORT WebUIMessageHandler {
   // Called when a RenderView is reused to display a page (i.e. reload).
   void RenderViewReused();
 
+  // Called when the owning RenderFrameHost has started swapping out.
+  void RenderFrameHostSwappingOut();

[Charlie Reis, 2016/06/06 21:09:52]

Kind of unfortunate to be including something about swap out in content/public,
even if it's in the private section.  If it's not easy to avoid, can you include
a TODO to remove this when WebUI gets a pointer to its owning RFH (with a bug
number)?

[Dan Beam, 2016/06/06 23:41:46]

i think it's easy to avoid

[tommycli, 2016/06/07 17:46:07]

Done.

+
   // TODO(dbeam): disallow JavaScript when a renderer process crashes.
   // http://crbug.com/610450