New thunk system for Pepper proxy and implementation

ppapi/shared_impl/resource_object_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_RESOURCE_OBJECT_BASE_H_
+#define PPAPI_SHARED_IMPL_RESOURCE_OBJECT_BASE_H_
+
+namespace ppapi {
+
+namespace thunk {
+class PPB_Graphics2D_API;
+class PPB_ImageData_API;
+}
+
+namespace shared_impl {
+
+class ResourceObjectBase {
+ public:
+
+  virtual thunk::PPB_Graphics2D_API* AsGraphics2D_API() { return NULL; }
+  virtual thunk::PPB_ImageData_API* AsImageData_API() { return NULL; }
+
+  template <typename T> T* GetAs() { return NULL; }
+};
+
+template<>
+inline thunk::PPB_Graphics2D_API* ResourceObjectBase::GetAs() {
+  return AsGraphics2D_API();
+}
+template<>
+inline thunk::PPB_ImageData_API* ResourceObjectBase::GetAs() {
+  return AsImageData_API();
+}
+
+}  // namespace shared_impl
+}  // namespace ppapi
+
+#endif  // PPAPI_SHARED_IMPL_RESOURCE_OBJECT_BASE_H_