linux-aura: Supports Compose key with XIM.

ui/events/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/events/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 792 matching lines @@
       return XF86XK_KbdBrightnessDown;
     case VKEY_KBD_BRIGHTNESS_UP:
       return XF86XK_KbdBrightnessUp;
 
     default:
       LOG(WARNING) << "Unknown keycode:" << keycode;
       return 0;
     }
 }
 
+bool IsXKeyEventFabricatedByIme(XEvent* xev) {
+  // XIM fabricates key events for the character compositions by XK_Multi_key.
+  // For example, when a user hits XK_Multi_key, XK_apostrophe, and XK_e in
+  // order to input "é", then XIM generates a key event with keycode=0 and
+  // state=0 for the composition, and the sequence of X11 key events will be
+  // XK_Multi_key, XK_apostrophe, **NoSymbol**, and XK_e.
+  //
+  // We have to send these fabricated key events to XIM so it can correctly
+  // handle the character compositions.
+  const bool fabricated_by_xim = xev->xkey.keycode == 0 && xev->xkey.state == 0;
+
+  return fabricated_by_xim;
+}
+
 }  // namespace ui