Convert resources to take an instance key instead of an Instance*.

ppapi/cpp/private/flash_message_loop.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_CPP_PRIVATE_FLASH_MESSAGE_LOOP_H_
 #define PPAPI_CPP_PRIVATE_FLASH_MESSAGE_LOOP_H_
 
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/cpp/resource.h"
 
 namespace pp {
 
-class Instance;
+class InstanceHandle;
 
 namespace flash {
 
 class MessageLoop : public Resource {
  public:
-  explicit MessageLoop(Instance* instance);
+  explicit MessageLoop(const InstanceHandle& instance);
   virtual ~MessageLoop();
 
   static bool IsAvailable();
 
   int32_t Run();
   void Quit();
 };
 
 }  // namespace flash
 }  // namespace pp
 
 #endif  // PPAPI_CPP_PRIVATE_FLASH_MESSAGE_LOOP_H_