Add a CodeToNativeKeycode helper that converts UIEvent code to native code.

ui/base/keycodes/usb_keycode_map.h

 // 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.
 
 // Data in this file was created by referencing:
 //  USB HID Usage Tables (v1.11) 27 June 2001
 //  HIToolbox/Events.h (Mac)
 
 #include <stdint.h>
 
@@ skipping 381 matching lines @@
   for (size_t i = 0; i < arraysize(usb_keycode_map); ++i) {
     if (usb_keycode_map[i].native_keycode == native_keycode) {
       if (usb_keycode_map[i].code != NULL)
         return usb_keycode_map[i].code;
       break;
     }
   }
   return InvalidKeyboardEventCode();
 }
 
+inline uint16_t CodeToNativeKeycode(const char* code) {
+  if (!code ||
+      strcmp(code, InvalidKeyboardEventCode()) == 0) {
+    return InvalidNativeKeycode();
+  }
+
+  for (size_t i = 0; i < arraysize(usb_keycode_map); ++i) {
+    if (usb_keycode_map[i].code &&
+        strcmp(usb_keycode_map[i].code, code) == 0) {
+      return usb_keycode_map[i].native_keycode;
+    }
+  }
+  return InvalidNativeKeycode();
+}
+
 // USB keycodes
 // Note that USB keycodes are not part of any web standard.
 // Please don't use USB keycodes in new code.
 
 inline uint16_t InvalidUsbKeycode() {
   return usb_keycode_map[0].usb_keycode;
 }
 
 inline uint16_t UsbKeycodeToNativeKeycode(uint32_t usb_keycode) {
   // Deal with some special-cases that don't fit the 1:1 mapping.
@@ skipping 19 matching lines @@
   return InvalidUsbKeycode();
 }
 
 inline const char* UsbKeycodeToCode(uint32_t usb_keycode) {
   for (size_t i = 0; i < arraysize(usb_keycode_map); ++i) {
     if (usb_keycode_map[i].usb_keycode == usb_keycode)
       return usb_keycode_map[i].code;
   }
   return InvalidKeyboardEventCode();
 }