Add check on invalid file descriptor at both broker and renderer sides.

content/ppapi_plugin/ppapi_thread.cc

 // Copyright (c) 2011 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 "content/ppapi_plugin/ppapi_thread.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/process_util.h"
@@ skipping 282 matching lines @@
   if (!init_result) {
     delete dispatcher;
     return false;
   }
 
   handle->name = plugin_handle.name;
 #if defined(OS_POSIX)
   // On POSIX, pass the renderer-side FD.
   handle->socket = base::FileDescriptor(::dup(dispatcher->GetRendererFD()),
                                         true);
+  if (handle->socket.fd == -1)
+    return false;
 #endif
 
   // From here, the dispatcher will manage its own lifetime according to the
   // lifetime of the attached channel.
   return true;
 }