Make sure channel-associated interface pointers are always safe to call.

ipc/ipc_channel_mojo.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ipc/ipc_channel_mojo.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
@@ skipping 461 matching lines @@
     const std::string& name,
     const GenericAssociatedInterfaceFactory& factory) {
   base::AutoLock locker(associated_interface_lock_);
   auto result = associated_interfaces_.insert({ name, factory });
   DCHECK(result.second);
 }
 
 void ChannelMojo::GetGenericRemoteAssociatedInterface(
     const std::string& name,
     mojo::ScopedInterfaceEndpointHandle handle) {
-  if (message_reader_)
+  if (message_reader_) {
     message_reader_->GetRemoteInterface(name, std::move(handle));
+  } else {
+    mojo::GetIsolatedInterface(std::move(handle));

[Ken Rockot(use gerrit already), 2017/03/24 19:20:03]

nit: I might consider documenting here why we do this and why it's OK.

[yzshen1, 2017/03/25 07:18:15]

Done.

+  }
 }
 
 }  // namespace IPC