New thunk system for Pepper proxy and implementation

ppapi/shared_impl/function_group_base.h

+// Copyright (c) 2011 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.
+
+#ifndef PPAPI_SHARED_IMPL_FUNCTION_GROUP_BASE_H_
+#define PPAPI_SHARED_IMPL_FUNCTION_GROUP_BASE_H_
+
+namespace ppapi {
+
+namespace thunk {
+class ResourceCreationAPI;
+}
+
+namespace shared_impl {
+
+class FunctionGroupBase {
+ public:
+  // Dynamic casting for this object. Returns the pointer to the given type if
+  // it's supported.
+  virtual thunk::ResourceCreationAPI* AsResourceCreation() { return NULL; }
+
+  template <typename T> T* GetAs() { return NULL; }
+};
+
+template<>
+inline thunk::ResourceCreationAPI* FunctionGroupBase::GetAs() {
+  return AsResourceCreation();
+}
+
+}  // namespace shared_impl
+}  // namespace ppapi
+
+#endif  // PPAPI_SHARED_IMPL_FUNCTION_GROUP_BASE_H_