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

ppapi/cpp/trusted/file_chooser_trusted.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_TRUSTED_FILE_CHOOSER_TRUSTED_H_
 #define PPAPI_CPP_TRUSTED_FILE_CHOOSER_TRUSTED_H_
 
 #include <string>
 
 #include "ppapi/cpp/dev/file_chooser_dev.h"
 
 namespace pp {
 
 class FileChooser_Trusted : public FileChooser_Dev {
  public:
   /// Creates an is_null() FileChooser_Trusted object.
   FileChooser_Trusted();
 
-  FileChooser_Trusted(const Instance* instance,
+  FileChooser_Trusted(const InstanceHandle& instance,
                       PP_FileChooserMode_Dev mode,
                       const Var& accept_mime_types,
                       bool save_as,
                       const std::string& suggested_file_name);
 
   FileChooser_Trusted(const FileChooser_Trusted& other);
 
   FileChooser_Trusted& operator=(const FileChooser_Trusted& other);
 
   // Overrides of method in superclass. This shows without requiring a user
   // gesture (and can also show save dialogs).
   virtual int32_t Show(const CompletionCallback& cc);
 
  private:
   bool save_as_;
   std::string suggested_file_name_;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_TRUSTED_FILE_CHOOSER_TRUSTED_H_