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

ppapi/cpp/fullscreen.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_FULLSCREEN_H_
 #define PPAPI_CPP_FULLSCREEN_H_
 
+#include "ppapi/cpp/instance_handle.h"
+
 /// @file
 /// This file defines the API for handling transitions of a module instance to
 /// and from fullscreen mode.
 
 namespace pp {
 
-class Instance;
 class Size;
 
 /// The Fullscreen class allowing you to check and toggle fullscreen mode.
 class Fullscreen {
  public:
   /// A constructor for creating a <code>Fullscreen</code>.
   ///
-  /// @param[in] instance The instance that will own the new
-  /// <code>Fullscreen</code>.
-  Fullscreen(Instance* instance);
+  /// @param[in] instance The instance with which this resource will be
+  /// associated.
+  explicit Fullscreen(const InstanceHandle& instance);
 
   /// Destructor.
   virtual ~Fullscreen();
 
   /// IsFullscreen() checks whether the module instance is currently in
   /// fullscreen mode.
   ///
   /// @return <code>true</code> if the module instance is in fullscreen mode,
   /// <code>false</code> if the module instance is not in fullscreen mode.
   bool IsFullscreen();
@@ skipping 21 matching lines @@
   /// will be resized to this size when SetFullscreen() is called to enter
   /// fullscreen mode.
   ///
   /// @param[out] size The size of the entire screen in pixels.
   ///
   /// @return <code>true</code> on success or <code>false</code> on
   /// failure.
   bool GetScreenSize(Size* size);
 
  private:
-  Instance* instance_;
+  InstanceHandle instance_;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_FULLSCREEN_H_