Cloning a bunch of stuff from the native_client repository at r6528

ppapi/native_client/src/shared/ppapi_proxy/upcall.srpc

+# 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.
+
+# RPC methods handled by the upcall channel instead of the main channel.
+{
+ 'name': 'PppUpcallRpc',
+ 'rpcs': [
+          # Implements work scheduling on the main thread after a delay.
+          {'name': 'PPB_Core_CallOnMainThread',
+           'inputs': [['delay_in_milliseconds', 'int32_t'],
+                      ['callback_id', 'int32_t'],  # PP_CompletionCallback
+                      ['result', 'int32_t'],  # int32_t
+                     ],
+           'outputs': []
+          },
+         ]
+}