Separate Remote InterfaceProvider again, and add a new client lib type for it.

services/shell/public/cpp/lib/remote_interface_registry.cc

+// Copyright 2016 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 "services/shell/public/cpp/remote_interface_registry.h"
+
+namespace shell {
+
+RemoteInterfaceRegistry::RemoteInterfaceRegistry(
+    mojom::InterfaceProviderPtr remote_interfaces)
+    : remote_interfaces_(std::move(remote_interfaces)) {}
+RemoteInterfaceRegistry::~RemoteInterfaceRegistry() {}
+
+mojom::InterfaceProvider* RemoteInterfaceRegistry::GetInterfaceProvider() {
+  return remote_interfaces_.get();
+}
+
+void RemoteInterfaceRegistry::SetConnectionLostClosure(
+    const base::Closure& connection_lost_closure) {
+  remote_interfaces_.set_connection_error_handler(connection_lost_closure);
+}
+
+void RemoteInterfaceRegistry::GetInterface(
+    const std::string& name,
+    mojo::ScopedMessagePipeHandle request_handle) {
+  remote_interfaces_->GetInterface(name, std::move(request_handle));
+}
+
+void RemoteInterfaceRegistry::ClearBinders() {
+  binders_.clear();
+}
+
+}  // namespace shell