Avoid calling Abort from main thread on IBinding created on another thread. I...

plugin/npapi_host_control/win/stream_operation.h

 // Copyright 2009, Google Inc.  All rights reserved.
 // Portions of this file were adapted from the Mozilla project.
 // See https://developer.mozilla.org/en/ActiveX_Control_for_Hosting_Netscape_Plug-ins_in_IE
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
@@ skipping 104 matching lines @@
   // Assign/Retrieve the opaque NPAPI-provided callback data for the
   // stream-operation.
   void SetNotifyData(void *notify_data) {
     notify_data_ = notify_data;
   }
 
   void* GetNotifyData() {
     return notify_data_;
   }
 
-  // Call to request that the streaming operation terminate early.  After this
-  // has been called, no further data notifications will take place.  The next,
-  // and last notification will be through
-  // IBindStatusCallback::OnStopBinding(...).
+  // Call to request that the streaming operation terminate early. As soon as
+  // the streaming thread sees the request has been cancelled, it aborts its
+  // binding.
   HRESULT RequestCancellation();
 
 BEGIN_COM_MAP(StreamOperation)
   COM_INTERFACE_ENTRY(IBindStatusCallback)
 END_COM_MAP()
 
   // To allow interaction with non-thread-safe NPAPI plug-in modules, the
   // streaming code uses Windows message pumps to serialize the interactions
   // calling back into the plug-in on the thread in which the plug-in resides.
   // When information about the state of the streaming request is provided
@@ skipping 123 matching lines @@
   // Value used to indicate the streaming operation should stop processing
   // input data.
   bool cancel_requested_;
 
   static unsigned int __stdcall WorkerProc(void *worker_arguments);
 
   DISALLOW_COPY_AND_ASSIGN(StreamOperation);
 };
 
 #endif  // O3D_PLUGIN_NPAPI_HOST_CONTROL_WIN_STREAM_OPERATION_H_