Rename NaCl/pepper gamepad interface from _dev to stable

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

 # 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.
 
 # RPC methods used to implement PPB_Gamepad interface.
-# See ppapi/c/dev/ppb_gamepad_dev.h for interface details.
+# See ppapi/c/ppb_gamepad.h for interface details.
 {
  'name': 'PpbGamepadRpc',
  'rpcs': [
-          {'name': 'PPB_Gamepad_SampleGamepads',
+          {'name': 'PPB_Gamepad_Sample',
            'inputs': [['instance', 'PP_Instance']],
-           'outputs': [['data', 'char[]']]            # PP_GamepadsData_Dev
+           'outputs': [['data', 'char[]']]            # PP_GamepadsSampleData
           },
          ]
 }