[Extensions] Make port creation synchronous in unload handlers

extensions/renderer/messaging_bindings.h

Index: extensions/renderer/messaging_bindings.h
diff --git a/extensions/renderer/messaging_bindings.h b/extensions/renderer/messaging_bindings.h
index b0e9fe780b34f3c9a6ca536c0c19fd6544a62fcf..c2a2810d608316e18f00e3ad37abd8b874dfaa61 100644
--- a/extensions/renderer/messaging_bindings.h
+++ b/extensions/renderer/messaging_bindings.h
@@ -117,6 +117,15 @@ class MessagingBindings : public ObjectBackedNativeHandler {
   // The next available local id for a port.
   int next_local_id_ = 0;
 
+  // The number of ports created in the 'beforeunload' event handler.
+  int ports_created_in_before_unload_ = 0;

[lazyboy, 2016/11/11 01:39:17]

since these are unsigned, can make them unsigned int or size_t.

[Devlin, 2016/11/12 01:24:30]

Done.

+
+  // The number of ports created in the 'unload' event handler.
+  int ports_created_in_unload_ = 0;
+
+  // The number of ports created during the normal lifetime of the context.

[lazyboy, 2016/11/11 01:39:17]

nit: replace "normal lifetime" with something that explicitly states that this
is not during unload or beforeunload.

[Devlin, 2016/11/12 01:24:30]

Done.

+  int ports_created_normal_ = 0;
+
   base::WeakPtrFactory<MessagingBindings> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagingBindings);