Remove the window script object tear-down special-case.

content/renderer/webplugin_delegate_proxy.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/renderer/webplugin_delegate_proxy.h"
 
 #if defined(TOOLKIT_USES_GTK)
 #include <gtk/gtk.h>
 #endif
 
@@ skipping 201 matching lines @@
     // channel, this avoids a race where this renderer asks a new connection to
     // the same plugin between now and the time 'this' is actually deleted.
     // Destroying the channel host is what releases the channel name -> FD
     // association on POSIX, and if we ask for a new connection before it is
     // released, the plugin will give us a new FD, and we'll assert when trying
     // to associate it with the channel name.
     channel_host_ = NULL;
   }
 
   if (window_script_object_) {
-    // The ScriptController deallocates this object independent of its ref count
-    // to avoid leaks if the plugin forgets to release it.  So mark the object
-    // invalid to avoid accessing it past this point.  Note: only do this after
-    // the DestroyInstance message in case the window object is scripted by the
-    // plugin in NPP_Destroy.
-    window_script_object_->DeleteSoon(false);
+    // Release the window script object, if the plugin didn't already.
+    // If we don't do this then it will linger until the last plugin instance is
+    // destroyed.  In the meantime, though, the frame that it refers to may have
+    // been destroyed by WebKit, at which point WebKit will forcibly deallocate
+    // the window script object.  The window script object stub is unique to the
+    // plugin instance, so this won't affect other instances.
+    window_script_object_->DeleteSoon();
   }
 
   plugin_ = NULL;
 
   MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 // Returns true if the given Silverlight 'background' value corresponds to
 // one that should make the plugin transparent. See:
 // http://msdn.microsoft.com/en-us/library/cc838148(VS.95).aspx
@@ skipping 1150 matching lines @@
 }
 #endif
 
 void WebPluginDelegateProxy::OnURLRedirectResponse(bool allow,
                                                    int resource_id) {
   if (!plugin_)
     return;
 
   plugin_->URLRedirectResponse(allow, resource_id);
 }