Add GetUsbKeyCode dev interface for Pepper key events

ppapi/api/ppb_input_event.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 Input Event interfaces.
  */
 
 label Chrome {
@@ skipping 664 matching lines @@
    * @param[in] time_stamp A <code>PP_TimeTicks</code> indicating the time
    * when the event occurred.
    *
    * @param[in]  modifiers A bit field combination of the
    * <code>PP_InputEvent_Modifier</code> flags.
    *
    * @param[in] key_code This value reflects the DOM KeyboardEvent
    * <code>keyCode</code> field. Chrome populates this with the Windows-style
    * Virtual Key code of the key.
    *
+   * @param[in] usb_scan_code This value reflects the USB scancode that
+   * generated this keyboard event.
+   *
    * @param[in] character_text This value represents the typed character as a
    * UTF-8 string.
    *
    * @return A <code>PP_Resource</code> containing the new keyboard input
    * event.
    */
   PP_Resource Create([in] PP_Instance instance,
                      [in] PP_InputEvent_Type type,
                      [in] PP_TimeTicks time_stamp,
                      [in] uint32_t modifiers,
                      [in] uint32_t key_code,
+                     [in] uint32_t usb_scan_code,
                      [in] PP_Var character_text);
 
   /**
    * IsKeyboardInputEvent() determines if a resource is a keyboard event.
    * 
    * @param[in] resource A <code>PP_Resource</code> corresponding to an event.
    *
    * @return <code>PP_TRUE</code> if the given resource is a valid input event.
    */
   PP_Bool IsKeyboardInputEvent([in] PP_Resource resource);
 
   /**
    * GetKeyCode() returns the DOM keyCode field for the keyboard event.
    * Chrome populates this with the Windows-style Virtual Key code of the key.
    *
    * @param[in] key_event A <code>PP_Resource</code> corresponding to a
    * keyboard event.
    *
    * @return The DOM keyCode field for the keyboard event.
    */
   uint32_t GetKeyCode([in] PP_Resource key_event);
 
   /**
+   * GetUsbScanCode_Dev() returns the USB scancode that corresponds to the key
+   * that generated this keyboard event.
+   *
+   * @param[in] key_event A <code>PP_Resource</code> corresponding to a
+   * keyboard event.
+   *
+   * @return The USB scancode field for the keyboard event.
+   */
+  uint32_t GetUsbScanCode_Dev([in] PP_Resource key_event);

[brettw, 2012/02/09 19:19:44]

We need to keep backwards compat for old users of this interface. You can see
how MouseInputEvent has two versions, 1.1 and 1.0, and two create functions.
You'll also need to set the version on your new function to be 1.1. 

Over IM, I thought we had discussed putting the accessor on a new dev interface.
We don't really have a facility to add dev functions to non-dev interfaces. So
either I would make a separate interface in the dev directory, or leave off the
_Dev for this name (knowing that we're committing to supporting the function).

[Wez, 2012/02/16 19:18:51]

Yes, the plan is to have a new dev interface with a single accessor that takes
an input-event PP_Resource and returns the USB-style key code.  This patch-set
pre-dates our IM, and deals more with the plumbing side of things.

Gary: Is the new patch-set almost ready for review?

[garykac, 2012/02/16 20:45:03]

Patchset 5 and beyond have the updated code (where there's a separate dev
interface that contain the USB accessors).

+
+  /**
    * GetCharacterText() returns the typed character as a UTF-8 string for the
    * given character event.
    *
    * @param[in] character_event A <code>PP_Resource</code> corresponding to a
    * keyboard event.
    *
    * @return A string var representing a single typed character for character
    * input events. For non-character input events the return value will be an
    * undefined var.
    */
   PP_Var GetCharacterText([in] PP_Resource character_event);
 };