PPAPI NaCl Proxy: optimize PPB_Fullscreen::IsFullscreen.

ppapi/native_client/src/shared/ppapi_proxy/ppb_fullscreen.srpc

 # 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.
 
 # RPC methods used to implement PPB_Fullscreen interface.
 # See ppapi/c/dev/ppb_fullscreen.h for interface details.
 {
  'name': 'PpbFullscreenRpc',
  'rpcs': [
-          {'name': 'PPB_Fullscreen_IsFullscreen',
-           'inputs': [['instance', 'PP_Instance'],    # PP_Instance
-                     ],
-           'outputs': [['success', 'int32_t'],        # PP_Bool
-                      ]
-          },
           {'name': 'PPB_Fullscreen_SetFullscreen',
            'inputs': [['instance', 'PP_Instance'],    # PP_Instance
                       ['fullscreen', 'int32_t'],      # PP_Bool
                      ],
            'outputs': [['success', 'int32_t'],        # PP_Bool
                       ]
           },
           {'name': 'PPB_Fullscreen_GetScreenSize',
            'inputs': [['instance', 'PP_Instance'],    # PP_Instance
                      ],
            'outputs': [['size', 'char[]'],            # PP_Size*
                        ['success', 'int32_t'],        # PP_Bool
                       ]
           },
          ]
 }