Mojo: Log an error on the remote message pipe leak condition.[1]

mojo/system/remote_message_pipe_unittest.cc

 // Copyright 2014 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 <stdint.h>
 #include <string.h>
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 348 matching lines @@
                              MOJO_READ_MESSAGE_FLAG_NONE));
 
   buffer_size = static_cast<uint32_t>(sizeof(buffer));
   EXPECT_EQ(MOJO_RESULT_OK,
             mp1->ReadMessage(1,
                              buffer, &buffer_size,
                              NULL, NULL,
                              MOJO_READ_MESSAGE_FLAG_NONE));
   EXPECT_EQ(sizeof(world), static_cast<size_t>(buffer_size));
   EXPECT_STREQ(world, buffer);
+
+  mp0->Close(0);
+  mp1->Close(1);
+  mp2->Close(0);
+  mp3->Close(1);
 }
 
 TEST_F(RemoteMessagePipeTest, CloseBeforeConnect) {
   const char hello[] = "hello";
   char buffer[100] = { 0 };
   uint32_t buffer_size = static_cast<uint32_t>(sizeof(buffer));
   Waiter waiter;
 
   // Connect message pipes. MP 0, port 1 will be attached to channel 0 and
   // connected to MP 1, port 0, which will be attached to channel 1. This leaves
@@ skipping 206 matching lines @@
 
     mp1->Close(1);
 
     RestoreInitialState();
   }
 }
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo