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diff --git a/ppapi/shared_impl/resource_tracker.h b/ppapi/shared_impl/resource_tracker.h
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+++ b/ppapi/shared_impl/resource_tracker.h
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+// 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.
+
+#ifndef PPAPI_SHARED_IMPL_RESOURCE_TRACKER_H_
+#define PPAPI_SHARED_IMPL_RESOURCE_TRACKER_H_
+
+#include <set>
+
+#include "base/basictypes.h"
+#include "base/hash_tables.h"
+#include "base/memory/linked_ptr.h"
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/c/pp_resource.h"
+
+namespace ppapi {
+
+class Resource;
+
+class ResourceTracker {
+ public:
+  ResourceTracker();
+  virtual ~ResourceTracker();
+
+  // The returned pointer will be NULL if there is no resource. The reference
+  // count of the resource is unaffected.
+  Resource* GetResource(PP_Resource res) const;
+
+  void AddRefResource(PP_Resource res);
+  void ReleaseResource(PP_Resource res);
+
+  // Notifies the tracker that a new instance has been created. This must be
+  // called before creating any resources associated with the instance.
+  void DidCreateInstance(PP_Instance instance);
+
+  // Called when an instance is being deleted. All plugin refs for the
+  // associated resources will be force freed, and the resources (if they still
+  // exist) will be disassociated from the instance.
+  void DidDeleteInstance(PP_Instance instance);
+
+  // Returns the number of resources associated with the given instance.
+  // Returns 0 if the instance isn't known.
+  int GetLiveObjectsForInstance(PP_Instance instance) const;
+
+ protected:
+  // This calls AddResource and RemoveResource.
+  friend class Resource;
+
+  // Adds the given resource to the tracker, associating it with the instance
+  // stored in the resource object. The new resource ID is returned, and the
+  // resource will have 0 plugin refcount. This is called by the resource
+  // constructor.
+  //
+  // Returns 0 if the resource could not be added.
+  virtual PP_Resource AddResource(Resource* object);
+
+  // The opposite of AddResource, this removes the tracking information for
+  // the given resource. It's called from the resource destructor.
+  virtual void RemoveResource(Resource* object);
+
+ private:
+  typedef std::set<PP_Resource> ResourceSet;
+
+  struct InstanceData {
+    // Lists all resources associated with the given instance as non-owning
+    // pointers. This allows us to notify those resources that the instance is
+    // going away (otherwise, they may crash if they outlive the instance).
+    ResourceSet resources;
+  };
+  typedef base::hash_map<PP_Instance, linked_ptr<InstanceData> > InstanceMap;
+
+  InstanceMap instance_map_;
+
+  // For each PP_Resource, keep the object pointer and a plugin use count.
+  // This use count is different then Resource object's RefCount, and is
+  // manipulated using this AddRefResource/UnrefResource. When the plugin use
+  // count is positive, we keep an extra ref on the Resource on
+  // behalf of the plugin. When it drops to 0, we free that ref, keeping
+  // the resource in the list.
+  //
+  // A resource will be in this list as long as the object is alive.
+  typedef std::pair<Resource*, int> ResourceAndRefCount;
+  typedef base::hash_map<PP_Resource, ResourceAndRefCount> ResourceMap;
+  ResourceMap live_resources_;
+
+  int32 last_resource_value_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResourceTracker);
+};
+
+}  // namespace ppapi
+
+#endif  // PPAPI_SHARED_IMPL_RESOURCE_TRACKER_H_