Implement the gamepad API in the IPC proxy

ppapi/host/host_message_context.cc

+// Copyright (c) 2012 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 "ppapi/host/host_message_context.h"
+
+namespace ppapi {
+namespace host {
+
+HostMessageContext::HostMessageContext(
+    const ppapi::proxy::ResourceMessageCallParams& cp)
+    : params(cp) {
+}
+
+HostMessageContext::~HostMessageContext() {
+}
+
+ppapi::proxy::ResourceMessageReplyParams HostMessageContext::MakeReplyParams() {
+  return ppapi::proxy::ResourceMessageReplyParams(params.pp_resource(),
+                                                  params.sequence());
+}
+
+}  // namespace host
+}  // namespace ppapi