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

webkit/plugins/ppapi/host_var_tracker.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_var_tracker.h"
 
 #include "base/logging.h"
 #include "ppapi/c/pp_var.h"
 #include "webkit/plugins/ppapi/host_array_buffer_var.h"
 #include "webkit/plugins/ppapi/npobject_var.h"
@@ skipping 82 matching lines @@
 
 int HostVarTracker::GetLiveNPObjectVarsForInstance(PP_Instance instance) const {
   DCHECK(CalledOnValidThread());
 
   InstanceMap::const_iterator found = instance_map_.find(instance);
   if (found == instance_map_.end())
     return 0;
   return static_cast<int>(found->second->size());
 }
 
-void HostVarTracker::ForceFreeNPObjectsForInstance(PP_Instance instance) {
+void HostVarTracker::DidDeleteInstance(PP_Instance instance) {
   DCHECK(CalledOnValidThread());
 
   InstanceMap::iterator found_instance = instance_map_.find(instance);
   if (found_instance == instance_map_.end())
     return;  // Nothing to do.
   NPObjectToNPObjectVarMap* np_object_map = found_instance->second.get();
 
   // Force delete all var references. It's possible that deleting an object "A"
   // will cause it to delete another object "B" it references, thus removing "B"
   // from instance_map_. Therefore, we need to make a copy over which we can
   // iterate safely. Furthermore, the maps contain WeakPtrs so that we can
   // detect if the object is gone so that we don't dereference invalid memory.
   NPObjectToNPObjectVarMap np_object_map_copy = *np_object_map;
   NPObjectToNPObjectVarMap::iterator cur_var =
       np_object_map_copy.begin();
   while (cur_var != np_object_map_copy.end()) {
     NPObjectToNPObjectVarMap::iterator current = cur_var++;
     ForceReleaseNPObject(current->second);
     np_object_map->erase(current->first);
   }
 
   // Remove the record for this instance since it should be empty.
   DCHECK(np_object_map->empty());
   instance_map_.erase(found_instance);
 }
 
 void HostVarTracker::ForceReleaseNPObject(
     const base::WeakPtr< ::ppapi::NPObjectVar>& object) {
   // There's a chance that the object was already deleted before we got here.
-  // See ForceFreeNPObjectsForInstance for further explanation. If the object
-  // was deleted, the WeakPtr will return NULL.
+  // See DidDeleteInstance for further explanation. If the object was deleted,
+  // the WeakPtr will return NULL.
   if (!object.get())
     return;
   object->InstanceDeleted();
   VarMap::iterator iter = live_vars_.find(object->GetExistingVarID());
   if (iter == live_vars_.end()) {
     NOTREACHED();
     return;
   }
   iter->second.ref_count = 0;
   DCHECK(iter->second.track_with_no_reference_count == 0);
   DeleteObjectInfoIfNecessary(iter);
 }
 
 }  // namespace ppapi
 }  // namespace webkit