Actually free plugin implement vars when running out of process when the

ppapi/proxy/ppp_instance_proxy.cc

 // Copyright (c) 2012 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 "ppapi/proxy/ppp_instance_proxy.h"
 
 #include <algorithm>
 
 #include "ppapi/c/pp_var.h"
 #include "ppapi/c/ppb_core.h"
@@ skipping 201 matching lines @@
   }
 
   DCHECK(combined_interface_.get());
   *result = combined_interface_->DidCreate(instance,
                                            static_cast<uint32_t>(argn.size()),
                                            &argn_array[0], &argv_array[0]);
 }
 
 void PPP_Instance_Proxy::OnPluginMsgDidDestroy(PP_Instance instance) {
   combined_interface_->DidDestroy(instance);
-  PpapiGlobals::Get()->GetResourceTracker()->DidDeleteInstance(instance);
+
+  PpapiGlobals* globals = PpapiGlobals::Get();
+  globals->GetResourceTracker()->DidDeleteInstance(instance);
+  globals->GetVarTracker()->DidDeleteInstance(instance);
+
   static_cast<PluginDispatcher*>(dispatcher())->DidDestroyInstance(instance);
 }
 
 void PPP_Instance_Proxy::OnPluginMsgDidChangeView(
     PP_Instance instance,
     const ViewData& new_data,
     PP_Bool flash_fullscreen) {
   PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
   if (!dispatcher)
     return;
@@ skipping 31 matching lines @@
   // with. The plugin will normally take an additional reference which will keep
   // the resource alive in the plugin (and the one reference in the renderer
   // representing all plugin references).
   // Once all references at the plugin side are released, the renderer side will
   // be notified and release the reference added in HandleDocumentLoad() above.
   PpapiGlobals::Get()->GetResourceTracker()->ReleaseResource(plugin_loader);
 }
 
 }  // namespace proxy
 }  // namespace ppapi