Fix some runtime errors in mojo Connector.

mojo/public/bindings/lib/connector.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/public/bindings/lib/connector.h"
 
 #include <assert.h>
 #include <stdlib.h>
 
 #include <algorithm>
@@ skipping 77 matching lines @@
       break;
     }
 
     Message message;
     message.data = static_cast<MessageData*>(malloc(num_bytes));
     message.handles.resize(num_handles);
 
     rv = ReadMessage(message_pipe_,
                      message.data,
                      &num_bytes,
-                     &message.handles[0],
+                     message.handles.empty() ? NULL : &message.handles[0],
                      &num_handles,
                      MOJO_READ_MESSAGE_FLAG_NONE);
     if (rv != MOJO_RESULT_OK) {
       error_ = true;
       break;
     }
 
     incoming_receiver_->Accept(&message);
   }
 }
@@ skipping 11 matching lines @@
   }
 }
 
 void Connector::WriteOne(Message* message, bool* wait_to_write) {
   // TODO(darin): WriteMessage will eventually start generating an error that
   // it cannot accept more data. In that case, we'll need to wait on the pipe
   // to determine when we can try writing again. This flag will be set to true
   // in that case.
   *wait_to_write = false;
 
-  MojoResult rv = WriteMessage(message_pipe_,
-                               message->data,
-                               message->data->header.num_bytes,
-                               &message->handles[0],
-                               static_cast<uint32_t>(message->handles.size()),
-                               MOJO_WRITE_MESSAGE_FLAG_NONE);
+  MojoResult rv = WriteMessage(
+      message_pipe_,
+      message->data,
+      message->data->header.num_bytes,
+      message->handles.empty() ? NULL : &message->handles[0],
+      static_cast<uint32_t>(message->handles.size()),
+      MOJO_WRITE_MESSAGE_FLAG_NONE);
   if (rv == MOJO_RESULT_OK) {
     // The handles were successfully transferred, so we don't need the message
     // to track their lifetime any longer.
     message->handles.clear();
   } else {
     error_ = true;
   }
 }
 
 // ----------------------------------------------------------------------------
@@ skipping 18 matching lines @@
 }
 
 void Connector::Callback::OnHandleReady(MojoResult result) {
   assert(owner_);
   Connector* owner = NULL;
   std::swap(owner, owner_);
   owner->OnHandleReady(this, result);
 }
 
 }  // namespace mojo