Ensure clean up functions of MessageFilter are paired with their initialization functions

ipc/ipc_channel_proxy.cc

Index: ipc/ipc_channel_proxy.cc
diff --git a/ipc/ipc_channel_proxy.cc b/ipc/ipc_channel_proxy.cc
index 1e8bec057be0410d0694cd7343048ae3b53136bf..ddbe8267a5835b7acecb2cf8dee53cca78b5a4a1 100644
--- a/ipc/ipc_channel_proxy.cc
+++ b/ipc/ipc_channel_proxy.cc
@@ -212,6 +212,8 @@ void ChannelProxy::Context::OnChannelClosed() {
     return;
 
   for (auto& filter : pending_filters_) {
+    filter->OnFilterAdded(nullptr);

[Ken Rockot(use gerrit already), 2016/11/10 00:49:55]

nit: I think it's worth adding a comment here to clarify why all of these are
called.

[tzik, 2016/11/10 06:17:41]

Done.

+    filter->OnChannelConnected(peer_pid_);
     filter->OnChannelClosing();
     filter->OnFilterRemoved();
   }