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

ppapi/cpp/file_ref.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_REF_H_
 #define PPAPI_CPP_FILE_REF_H_
 
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/ppb_file_ref.h"
 #include "ppapi/cpp/resource.h"
 #include "ppapi/cpp/var.h"
 
 /// @file
 /// This file defines the API to create a file reference or "weak pointer" to a
 /// file in a file system.
 
 namespace pp {
 
 class CompletionCallback;
 class FileSystem;
 
 /// The <code>FileRef</code> class represents a "weak pointer" to a file in
 /// a file system.
 class FileRef : public Resource {
  public:
   /// Default constructor for creating an is_null() <code>FileRef</code>
   /// object.
   FileRef() {}
 
- /// A constructor used to create a <code>FileRef</code> and associate it with
-  /// the provided <code>Instance</code>.
+  /// A constructor used when you have an existing PP_Resource for a FileRef
+  /// and which to create a C++ object that takes an additional reference to
+  /// the resource.
   ///
-  /// @param[in] resource An <code>Instance</code>.
+  /// @param[in] resource A PP_Resource corresponding to file reference.
   explicit FileRef(PP_Resource resource);
 
-  /// A special structure used by the constructor that does not increment the
-  /// reference count of the underlying file reference.
-  struct PassRef {};
-
   /// A constructor used when you have received a PP_Resource as a return
   /// value that has already been reference counted.
   ///
   /// @param[in] resource A PP_Resource corresponding to file reference.
   FileRef(PassRef, PP_Resource resource);
 
   /// A constructor that creates a weak pointer to a file in the given file
   /// system. File paths are POSIX style.
   ///
   /// @param[in] file_system A <code>FileSystem</code> corresponding to a file
@@ skipping 94 matching lines @@
   /// @param[in] cc A <code>CompletionCallback</code> to be called upon
   /// completion of Rename().
   ///
   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
   int32_t Rename(const FileRef& new_file_ref, const CompletionCallback& cc);
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_FILE_REF_H_