EDK: Add handle rights checking to the various entrypoints.

mojo/edk/system/entrypoint_class.h

 // Copyright 2016 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 MOJO_EDK_SYSTEM_ENTRYPOINT_CLASS_H_
 #define MOJO_EDK_SYSTEM_ENTRYPOINT_CLASS_H_
 
 namespace mojo {
 namespace system {
 
 // Classes of "entrypoints"/"syscalls": Each dispatcher should support entire
 // classes of methods (and if they don't support a given class, they should
 // return |MOJO_RESULT_INVALID_ARGUMENT| for all the methods in that class).
 // Warning: A dispatcher method may be called even if the dispatcher's
 // |SupportsEntrypointClass()| indicates that the method's class is not
 // supported.
 enum class EntrypointClass {
+  // Not an entrypoint; all implementations of
+  // |Dispatcher::SupportsEntrypointClass()| should return true for this:
+  NONE,
+
   // |Dispatcher::ReadMessage()|, |Dispatcher::WriteMessage()|:
   MESSAGE_PIPE,
 
   // |Dispatcher::SetDataPipeProducerOptions()|,
   // |Dispatcher::GetDataPipeProducerOptions()|,
   // |Dispatcher::WriteData()|, |Dispatcher::BeginWriteData()|,
   // |Dispatcher::EndWriteData()|:
   DATA_PIPE_PRODUCER,
 
   // |Dispatcher::SetDataPipeConsumerOptions()|,
   // |Dispatcher::GetDataPipeConsumerOptions()|, |Dispatcher::ReadData()|,
   // |Dispatcher::BeginReadData()|, |Dispatcher::EndReadData()|:
   DATA_PIPE_CONSUMER,
 
   // |Dispatcher::DuplicateBufferHandle()|,
   // |Dispatcher::GetBufferInformation()|, |Dispatcher::MapBuffer()|:
   BUFFER,
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_ENTRYPOINT_CLASS_H_