PPAPI: Move IMEInputEvent and TextInput to stable.

ppapi/api/dev/ppp_text_input_dev.idl

-/* 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.
- */
-
-/**
- * This file defines the <code>PPP_TextInput_Dev</code> interface.
- */
-
-label Chrome {
-  M19 = 0.1
-};
-
-/**
- * <code>PPP_TextInput_Dev</code> is a set of function pointers that the
- * plugin has to implement to provide hints for text input system (IME).
- */
-interface PPP_TextInput_Dev {
-  /**
-   * Requests the plugin to send back the text around the current caret or
-   * selection by <code>PPB_TextInput_Dev::UpdateSurroundingText</code>.
-   * It is recommended to include the <code>desired_number_of_characters</code>
-   * characters before and after the selection, but not mandatory.
-   */
-  void RequestSurroundingText([in] PP_Instance instance,
-                              [in] uint32_t desired_number_of_characters);
-};