Handle F6 and F7 (brightness keys) in ash [part 3 of 3].

ui/base/keycodes/keyboard_code_conversion_x.cc

 // 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.
 
 #include "ui/base/keycodes/keyboard_code_conversion_x.h"
 
 #define XK_3270  // for XK_3270_BackTab
 #include <X11/keysym.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
@@ skipping 337 matching lines @@
       return VKEY_UNKNOWN;
 #endif
 
     // For supporting multimedia buttons on a USB keyboard.
     case XF86XK_AudioMute:
       return VKEY_VOLUME_MUTE;
     case XF86XK_AudioLowerVolume:
       return VKEY_VOLUME_DOWN;
     case XF86XK_AudioRaiseVolume:
       return VKEY_VOLUME_UP;
+    case XF86XK_MonBrightnessDown:
+      return VKEY_BRIGHTNESS_DOWN;
+    case XF86XK_MonBrightnessUp:
+      return VKEY_BRIGHTNESS_UP;
 
     // TODO(sad): some keycodes are still missing.
   }
   DLOG(WARNING) << "Unknown keysym: " << StringPrintf("0x%x", keysym);
   return VKEY_UNKNOWN;
 }
 
 uint16 GetCharacterFromXEvent(XEvent* xev) {
   char buf[6];
   int bytes_written = XLookupString(&xev->xkey, buf, 6, NULL, NULL);
@@ skipping 298 matching lines @@
     case VKEY_F23:
     case VKEY_F24:
       return XK_F1 + (keycode - VKEY_F1);
 
     case VKEY_VOLUME_MUTE:
       return XF86XK_AudioMute;
     case VKEY_VOLUME_DOWN:
       return XF86XK_AudioLowerVolume;
     case VKEY_VOLUME_UP:
       return XF86XK_AudioRaiseVolume;
+    case VKEY_BRIGHTNESS_DOWN:
+      return XF86XK_MonBrightnessDown;
+    case VKEY_BRIGHTNESS_UP:
+      return XF86XK_MonBrightnessUp;
 
     default:
       LOG(WARNING) << "Unknown keycode:" << keycode;
       return 0;
     }
 }
 
 }  // namespace ui