[spelling] existance to existence

dbus/object_manager.h

 // Copyright (c) 2013 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 DBUS_OBJECT_MANAGER_H_
 #define DBUS_OBJECT_MANAGER_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 193 matching lines @@
   // to this manager.
   std::vector<ObjectPath> GetObjects();
 
   // Returns the list of object paths, in an undefined order, of objects
   // implementing the interface named in |interface_name| known to this manager.
   std::vector<ObjectPath> GetObjectsWithInterface(
       const std::string& interface_name);
 
   // Returns a ObjectProxy pointer for the given |object_path|. Unlike
   // the equivalent method on Bus this will return NULL if the object
-  // manager has not been informed of that object's existance.
+  // manager has not been informed of that object's existence.
   ObjectProxy* GetObjectProxy(const ObjectPath& object_path);
 
   // Returns a PropertySet* pointer for the given |object_path| and
   // |interface_name|, or NULL if the object manager has not been informed of
-  // that object's existance or the interface's properties. The caller should
+  // that object's existence or the interface's properties. The caller should
   // cast the returned pointer to the appropriate type, e.g.:
   //   static_cast<Properties*>(GetProperties(object_path, my_interface));
   PropertySet* GetProperties(const ObjectPath& object_path,
                              const std::string& interface_name);
 
   // Instructs the object manager to refresh its list of managed objects;
   // automatically called by the D-Bus thread manager, there should never be
   // a need to call this manually.
   void GetManagedObjects();
 
@@ skipping 123 matching lines @@
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<ObjectManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ObjectManager);
 };
 
 }  // namespace dbus
 
 #endif  // DBUS_OBJECT_MANAGER_H_