Avoid leaking SerializedHandles.

ppapi/proxy/serialized_structs.h

 // 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.
 
 #ifndef PPAPI_PROXY_SERIALIZED_STRUCTS_H_
 #define PPAPI_PROXY_SERIALIZED_STRUCTS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 146 matching lines @@
   }
   void set_null_channel_handle() {
     set_channel_handle(IPC::InvalidPlatformFileForTransit());
   }
   bool IsHandleValid() const;
 
   Header header() const {
     return Header(type_, size_);
   }
 
+  // Closes the handle and sets it to invalid.
+  void Close();
+
   // Write/Read a Header, which contains all the data except the handle. This
   // allows us to write the handle in a platform-specific way, as is necessary
   // in NaClIPCAdapter to share handles with NaCl from Windows.
   static bool WriteHeader(const Header& hdr, Pickle* pickle);
   static bool ReadHeader(PickleIterator* iter, Header* hdr);
 
  private:
   // The kind of handle we're holding.
   Type type_;
 
@@ skipping 23 matching lines @@
 typedef base::SharedMemoryHandle ImageHandle;
 #else
 // On X Windows this is a SysV shared memory key.
 typedef int ImageHandle;
 #endif
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_SERIALIZED_STRUCTS_H_