NaCl cleanup: Stop connecting to the SRPC trusted command channel

components/nacl/loader/nacl_trusted_listener.cc

Index: components/nacl/loader/nacl_trusted_listener.cc
diff --git a/components/nacl/loader/nacl_trusted_listener.cc b/components/nacl/loader/nacl_trusted_listener.cc
index 4c67a09f490644cb55857f4ac307e779919ddea7..76d0cee523d6462593fd4021af128e8085182a52 100644
--- a/components/nacl/loader/nacl_trusted_listener.cc
+++ b/components/nacl/loader/nacl_trusted_listener.cc
@@ -5,6 +5,32 @@
 #include "components/nacl/loader/nacl_trusted_listener.h"
 
 #include "base/single_thread_task_runner.h"
+#include "ipc/message_filter.h"
+#include "native_client/src/public/chrome_main.h"
+
+namespace {
+
+// The OnChannelError() event must be processed in a MessageFilter so it can
+// be handled on the IO thread.  The main thread used by NaClListener is busy
+// in NaClChromeMainAppStart(), so it can't be used for servicing messages.
+class EOFMessageFilter : public IPC::MessageFilter {
+ public:
+  void OnChannelError() override {
+    // The renderer process dropped its connection to this process (the NaCl
+    // loader process), either because the <embed> element was removed
+    // (perhaps implicitly if the tab was closed) or because the renderer
+    // crashed.  The NaCl loader process should therefore exit.
+    //
+    // For SFI NaCl, trusted code does this exit voluntarily, but untrusted
+    // code cannot disable it.  However, for Non-SFI NaCl, the following exit
+    // call could be disabled by untrusted code.
+    NaClExit(0);
+  }
+ private:
+  ~EOFMessageFilter() override {}
+};
+
+}
 
 NaClTrustedListener::NaClTrustedListener(
     const IPC::ChannelHandle& handle,
@@ -17,6 +43,7 @@ NaClTrustedListener::NaClTrustedListener(
                                       ipc_task_runner,
                                       true,  /* create_channel_now */
                                       shutdown_event).Pass();
+  channel_->AddFilter(new EOFMessageFilter());
 }
 
 NaClTrustedListener::~NaClTrustedListener() {
@@ -35,10 +62,6 @@ bool NaClTrustedListener::OnMessageReceived(const IPC::Message& msg) {
   return false;
 }
 
-void NaClTrustedListener::OnChannelError() {
-  channel_->Close();
-}
-
 bool NaClTrustedListener::Send(IPC::Message* msg) {
   return channel_->Send(msg);
 }