Cloning a bunch of stuff from the native_client repository at r6528

ppapi/native_client/src/shared/ppapi_proxy/plugin_upcall.h

Index: ppapi/native_client/src/shared/ppapi_proxy/plugin_upcall.h
===================================================================
--- ppapi/native_client/src/shared/ppapi_proxy/plugin_upcall.h	(revision 0)
+++ ppapi/native_client/src/shared/ppapi_proxy/plugin_upcall.h	(revision 0)
@@ -0,0 +1,39 @@
+// Copyright (c) 2010 The Native Client Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+//
+// This is an early draft of background thread support.
+// Until it is complete, we assume that all functions proxy functions
+// (but CallOnMainThread) are called on the main thread.
+//
+// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+
+#ifndef NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_UPCALL_H_
+#define NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_UPCALL_H_
+
+#include "ppapi/c/pp_completion_callback.h"
+#include "ppapi/c/pp_resource.h"
+
+namespace ppapi_proxy {
+
+// Initialize the plugin side to allow upcalls (calls to the browser from
+// other than the PPAPI main thread).
+int32_t PluginUpcallStartup();
+
+// Shut down the plugin side for upcalls.
+void PluginUpcallShutdown();
+
+// The upcall for PPB_Core.CallOnMainThread.
+void PluginUpcallCoreCallOnMainThread(int32_t delay_in_milliseconds,
+                                      PP_CompletionCallback callback,
+                                      int32_t result);
+
+// The upcall for PPB_Graphics2D.Flush.
+int32_t PluginUpcallGraphics2DFlush(PP_Resource graphics_2d,
+                                    PP_CompletionCallback callback);
+
+}  // namespace ppapi_proxy
+
+#endif  // NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_UPCALL_H_