Implement out-of-process proxy for PPB_Buffer_Dev.

ppapi/cpp/dev/buffer_dev.cc

 // Copyright (c) 2010 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/cpp/dev/buffer_dev.h"
 
 #include "ppapi/c/dev/ppb_buffer_dev.h"
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
 #include "ppapi/cpp/module_impl.h"
@@ skipping 23 matching lines @@
   if (!has_interface<PPB_Buffer_Dev>())
     return;
 
   PassRefFromConstructor(get_interface<PPB_Buffer_Dev>()->Create(
       instance->pp_instance(), size));
   if (!get_interface<PPB_Buffer_Dev>()->Describe(pp_resource(), &size_) ||
       !(data_ = get_interface<PPB_Buffer_Dev>()->Map(pp_resource())))
     *this = Buffer_Dev();
 }
 
+Buffer_Dev::~Buffer_Dev() {
+  get_interface<PPB_Buffer_Dev>()->Unmap(pp_resource());
+}
+
 }  // namespace pp
-