Add blink::ServiceRegistry and expose it from LocalFrame and Platform.

content/renderer/mojo/blink_service_registry_impl.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 "content/renderer/mojo/blink_service_registry_impl.h"
+
+#include <utility>
+
+#include "content/common/mojo/service_registry_impl.h"
+
+namespace content {
+
+BlinkServiceRegistryImpl::BlinkServiceRegistryImpl(
+    base::WeakPtr<content::ServiceRegistry> service_registry)
+    : service_registry_(service_registry) {}
+
+BlinkServiceRegistryImpl::~BlinkServiceRegistryImpl() = default;
+
+void BlinkServiceRegistryImpl::connectToRemoteService(
+    const char* name,
+    mojo::ScopedMessagePipeHandle handle) {
+  if (!service_registry_)
+    return;
+
+  service_registry_->ConnectToRemoteService(name, std::move(handle));
+}
+
+}  // namespace content