Cleanup: Remove unneeded forward declarations in ppapi.

ppapi/cpp/var.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_VAR_H_
 #define PPAPI_CPP_VAR_H_
 
 #include <string>
 #include <vector>
 
 #include "ppapi/c/pp_module.h"
 #include "ppapi/c/pp_var.h"
 
 
 /// @file
 /// This file defines the API for handling the passing of data types between
 /// your module and the page.
 namespace pp {
 
-class Instance;
-
 /// A generic type used for passing data types between the module and the page.
 class Var {
  public:
   /// Special value passed to constructor to make <code>NULL</code>.
   struct Null {};
 
   /// Default constructor. Creates a <code>Var</code> of type
   /// <code>Undefined</code>.
   Var();
 
@@ skipping 254 matching lines @@
 
  protected:
   PP_Var var_;
   bool needs_release_;
 
  private:
   // Prevent an arbitrary pointer argument from being implicitly converted to
   // a bool at Var construction. If somebody makes such a mistake, (s)he will
   // get a compilation error.
   Var(void* non_scriptable_object_pointer);
-
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_VAR_H_