Add GetUsbKeyCode dev interface for Pepper key events

ppapi/cpp/input_event.h

Index: ppapi/cpp/input_event.h
diff --git a/ppapi/cpp/input_event.h b/ppapi/cpp/input_event.h
index 195ac08f3f14ac4116f68e33360e8fd1b0d28369..5c703bdae55b04dfab43bbeef0b7165713625c05 100644
--- a/ppapi/cpp/input_event.h
+++ b/ppapi/cpp/input_event.h
@@ -281,6 +281,9 @@ class KeyboardInputEvent : public InputEvent {
   /// <code>keyCode</code> field. Chrome populates this with the Windows-style
   /// Virtual Key code of the key.
   ///
+  /// @param[in] usb_scan_code The USB scancode that corresponds to the key
+  /// that generated this keyboard event.
+  ///
   /// @param[in] character_text This value represents the typed character as a
   /// UTF-8 string.
   KeyboardInputEvent(Instance* instance,
@@ -288,12 +291,17 @@ class KeyboardInputEvent : public InputEvent {
                      PP_TimeTicks time_stamp,
                      uint32_t modifiers,
                      uint32_t key_code,
+                     uint32_t usb_scan_code,
                      const Var& character_text);
 
   /// Returns the DOM keyCode field for the keyboard event.
   /// Chrome populates this with the Windows-style Virtual Key code of the key.
   uint32_t GetKeyCode() const;
 
+  /// Returns the USB scancode that corresponds to the key that generated this
+  /// keyboard event.
+  uint32_t GetUsbScanCode_Dev() const;
+
   /// Returns the typed character for the given character event.
   ///
   /// @return A string var representing a single typed character for character