If keysym is ASCII control or space keys, directly map to keycode.

ui/events/keycodes/keyboard_code_conversion_x.cc

Index: ui/events/keycodes/keyboard_code_conversion_x.cc
diff --git a/ui/events/keycodes/keyboard_code_conversion_x.cc b/ui/events/keycodes/keyboard_code_conversion_x.cc
index a4a810e23a43004eb09af168daa797968e6d8a23..0bf3c7fb1a11c9825558a5f3fa74de57e390250b 100644
--- a/ui/events/keycodes/keyboard_code_conversion_x.cc
+++ b/ui/events/keycodes/keyboard_code_conversion_x.cc
@@ -459,6 +459,12 @@ KeyboardCode FindVK(const T_MAP& key, const T_MAP* map, size_t size) {
   return VKEY_UNKNOWN;
 }
 
+bool IsAsciiControlKey(KeySym keysym) {
+  // 0xff01 to 0xff1f (instead of 0x01 to 0x1f) represent ASCII control in
+  // keysym world.
+  return (keysym > 0xff00 && keysym <= 0xff1f) || keysym == XK_Delete;

[Wez, 2014/10/24 01:17:44]

Why is XK_Delete in here? It's not a Ctrl+<ascii> keysym.

[Shu Chen, 2014/10/24 01:26:58]

Please refer to:
http://en.wikipedia.org/wiki/Control_character#In_ASCII

[Wez, 2014/10/24 01:43:14]

OK, understood; please make sure the CL description explains clearly _why_ we
need to do this.

+}
+
 }  // namespace
 
 // Get an ui::KeyboardCode from an X keyevent
@@ -492,7 +498,8 @@ KeyboardCode KeyboardCodeFromXKeyEvent(const XEvent* xev) {
   XLookupString(xkey, NULL, 0, &keysym, NULL);
   if (IsKeypadKey(keysym) || IsPrivateKeypadKey(keysym) ||
       IsCursorKey(keysym) || IsPFKey(keysym) || IsFunctionKey(keysym) ||
-      IsModifierKey(keysym)) {
+      IsModifierKey(keysym) || IsAsciiControlKey(keysym) ||
+      keysym == XK_space) {

[Wez, 2014/10/24 01:17:44]

could/should space go in IsAsciiControlKey?

[Shu Chen, 2014/10/24 01:26:58]

Ditto.

[Wez, 2014/10/24 01:43:14]

?

As currently laid out it's confusing that space is separate; is the reason we
want it in this list the same basic reason as for delete, escape, etc? If so
then why not put it in IsAsciiControlKey with a comment to explain why?

     return KeyboardCodeFromXKeysym(keysym);
   }