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

ppapi/cpp/file_system.h

 // Copyright (c) 2011 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_FILE_SYSTEM_H_
 #define PPAPI_CPP_FILE_SYSTEM_H_
 
 #include "ppapi/c/pp_file_info.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_stdint.h"
@@ skipping 12 matching lines @@
 /// associated with a file.
 class FileSystem : public Resource {
  public:
   /// Constructs an is_null() filesystem resource. If you use this constructor,
   /// you will have to assign it to a "real" FileSystem object before you can
   /// use it.
   FileSystem();
 
   /// This constructor creates a file system object of the given type.
   ///
-  /// @param[in] instance A <code>Instance</code> identifying the instance
-  /// with the file.
+  /// @param[in] instance The instance with which this resource will be
+  /// associated.
+  ///
   /// @param[in] type A file system type as defined by
   /// <code>PP_FileSystemType</code> enum.
-  FileSystem(Instance* instance, PP_FileSystemType type);
+  FileSystem(const InstanceHandle& instance, PP_FileSystemType type);
 
   /// Open() opens the file system. A file system must be opened before running
   /// any other operation on it.
   ///
   /// @param[in] expected_size The expected size of the file system.
   /// @param[in] cc A <code>PP_CompletionCallback</code> to be called upon
   /// completion of Open().
   ///
   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
   int32_t Open(int64_t expected_size, const CompletionCallback& cc);
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_FILE_SYSTEM_H_