Blocked volume up/down events that originated from remapped function keys.

ui/events/event_constants.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.
 
 #ifndef UI_EVENTS_EVENT_CONSTANTS_H_
 #define UI_EVENTS_EVENT_CONSTANTS_H_
 
 namespace ui {
 
 // Event types. (prefixed because of a conflict with windows headers)
@@ skipping 81 matching lines @@
   EF_ALTGR_DOWN          = 1 << 10,
   EF_MOD3_DOWN           = 1 << 11,
 };
 
 // Flags specific to key events
 enum KeyEventFlags {
   EF_NUMPAD_KEY         = 1 << 16,  // Key originates from number pad (Xkb only)
   EF_IME_FABRICATED_KEY = 1 << 17,  // Key event fabricated by the underlying
                                     // IME without a user action.
                                     // (Linux X11 only)
+  EF_FUNCTION_KEY       = 1 << 18,  // Key originates from function key row
 };
 
 // Flags specific to mouse events
 enum MouseEventFlags {
   EF_IS_DOUBLE_CLICK    = 1 << 16,
   EF_IS_TRIPLE_CLICK    = 1 << 17,
   EF_IS_NON_CLIENT      = 1 << 18,
   EF_FROM_TOUCH         = 1 << 19,  // Indicates this mouse event is generated
                                     // from an unconsumed touch/gesture event.
 };
@@ skipping 13 matching lines @@
   EP_PREDISPATCH,
   EP_PRETARGET,
   EP_TARGET,
   EP_POSTTARGET,
   EP_POSTDISPATCH
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_CONSTANTS_H_