Convert WriteMessage...() to use the new user pointer handling (see r285350).

mojo/system/message_pipe_dispatcher.cc

 // Copyright 2013 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.
 
 #include "mojo/system/message_pipe_dispatcher.h"
 
 #include "base/logging.h"
 #include "mojo/system/channel.h"
 #include "mojo/system/constants.h"
 #include "mojo/system/local_message_pipe_endpoint.h"
@@ skipping 161 matching lines @@
   // too.
   scoped_refptr<MessagePipeDispatcher> rv =
       new MessagePipeDispatcher(kDefaultCreateOptions);
   rv->Init(message_pipe_, port_);
   message_pipe_ = NULL;
   port_ = kInvalidPort;
   return scoped_refptr<Dispatcher>(rv.get());
 }
 
 MojoResult MessagePipeDispatcher::WriteMessageImplNoLock(
-    const void* bytes,
+    UserPointer<const void> bytes,
     uint32_t num_bytes,
     std::vector<DispatcherTransport>* transports,
     MojoWriteMessageFlags flags) {
   DCHECK(!transports || (transports->size() > 0 &&
                          transports->size() <= kMaxMessageNumHandles));
 
   lock().AssertAcquired();
 
-  if (!VerifyUserPointerWithSize<1>(bytes, num_bytes))
-    return MOJO_RESULT_INVALID_ARGUMENT;
   if (num_bytes > kMaxMessageNumBytes)
     return MOJO_RESULT_RESOURCE_EXHAUSTED;
 
   return message_pipe_->WriteMessage(port_, bytes, num_bytes, transports,
                                      flags);
 }
 
 MojoResult MessagePipeDispatcher::ReadMessageImplNoLock(
     UserPointer<void> bytes,
     UserPointer<uint32_t> num_bytes,
@@ skipping 61 matching lines @@
 
 // MessagePipeDispatcherTransport ----------------------------------------------
 
 MessagePipeDispatcherTransport::MessagePipeDispatcherTransport(
     DispatcherTransport transport) : DispatcherTransport(transport) {
   DCHECK_EQ(message_pipe_dispatcher()->GetType(), Dispatcher::kTypeMessagePipe);
 }
 
 }  // namespace system
 }  // namespace mojo