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

webkit/plugins/ppapi/host_globals.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 "webkit/plugins/ppapi/host_globals.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 222 matching lines @@
            !instance->module()->ReserveInstanceID(new_instance));
 
   instance_map_[new_instance] = instance;
 
   resource_tracker_.DidCreateInstance(new_instance);
   return new_instance;
 }
 
 void HostGlobals::InstanceDeleted(PP_Instance instance) {
   resource_tracker_.DidDeleteInstance(instance);
-  host_var_tracker_.ForceFreeNPObjectsForInstance(instance);
+  host_var_tracker_.DidDeleteInstance(instance);
   instance_map_.erase(instance);
 }
 
 void HostGlobals::InstanceCrashed(PP_Instance instance) {
   resource_tracker_.DidDeleteInstance(instance);
-  host_var_tracker_.ForceFreeNPObjectsForInstance(instance);
+  host_var_tracker_.DidDeleteInstance(instance);
 }
 
 PluginInstance* HostGlobals::GetInstance(PP_Instance instance) {
   DLOG_IF(ERROR, !CheckIdType(instance, ::ppapi::PP_ID_TYPE_INSTANCE))
       << instance << " is not a PP_Instance.";
   InstanceMap::iterator found = instance_map_.find(instance);
   if (found == instance_map_.end())
     return NULL;
   return found->second;
 }
 
 bool HostGlobals::IsHostGlobals() const {
   return true;
 }
 
 }  // namespace ppapi
 }  // namespace webkit