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

ppapi/cpp/url_response_info.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_URL_RESPONSE_INFO_H_
 #define PPAPI_CPP_URL_RESPONSE_INFO_H_
 
 #include "ppapi/c/ppb_url_response_info.h"
 #include "ppapi/cpp/resource.h"
 #include "ppapi/cpp/var.h"
 
 /// @file
 /// This file defines the API for examining URL responses.
 namespace pp {
 
 class FileRef;
 
 /// URLResponseInfo provides an API for examaning URL responses.
 class URLResponseInfo : public Resource {
  public:
   /// Default constructor. This constructor creates an <code>is_null</code>
   /// resource.
   URLResponseInfo() {}
 
-  /// A special structure used by the constructor that does not increment the
-  /// reference count of the underlying resource.
-  struct PassRef {};
-
   /// A constructor used when you have received a <code>PP_Resource</code> as a
   /// return value that has already been reference counted.
   ///
   /// @param[in] resource A <code>PP_Resource</code> corresponding to a
   /// resource.
   URLResponseInfo(PassRef, PP_Resource resource);
 
   /// The copy constructor for <code>URLResponseInfo</code>.
   URLResponseInfo(const URLResponseInfo& other);
 
@@ skipping 76 matching lines @@
   /// value if successful, <code>is_undefined Var</code> if an input parameter
   /// is invalid.
   Var GetHeaders() const {
     return GetProperty(PP_URLRESPONSEPROPERTY_HEADERS);
   }
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_URL_RESPONSE_INFO_H_