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..ce9bd44481ff8431ef4444d19372378a5187b95c 100644
--- a/ui/events/keycodes/keyboard_code_conversion_x.cc
+++ b/ui/events/keycodes/keyboard_code_conversion_x.cc
@@ -459,6 +459,15 @@ KeyboardCode FindVK(const T_MAP& key, const T_MAP* map, size_t size) {
   return VKEY_UNKNOWN;
 }
 
+// Check for ASCII Control or space keys which should directly map to key code
+// instead of stripping the modifier states and go through the fallback maps.

[Wez, 2014/10/24 22:29:18]

_Why_ should they do this, though?

What would Ctrl+Space result in without this fix?

What are the VKEYs we intend  to generate instead as a result of this?
KeyboardCodeFromXKeysym doesn't seem to have mappings for 0xff01-0xff1f, so
won't we generate VK_UNKNOWN...?

[Wez, 2014/10/24 22:31:22]

The example you give in CL description is AltGr+V -> Enter - but Enter isn't a
control nor space key, so won't match this case, nor is 'V'..?

[Shu Chen, 2014/10/25 05:46:19]

Enter is an ascii control key: keysym=0xff0d (XK_Return).

[Shu Chen, 2014/10/25 05:46:19]

The range 0xff01-0xff1f contains XK_Tab, XK_Return, XK_Backspace, etc. so
KeyboardCodeFromXKeysym can give out correct VKEYs.

+bool IsAsciiControlOrSpaceKey(KeySym keysym) {
+  // 0xff01 to 0xff1f (instead of 0x01 to 0x1f) represent ASCII control in
+  // keysym world.
+  return (keysym > 0xff00 && keysym <= 0xff1f) || keysym == XK_Delete ||
+      keysym == XK_Escape || keysym == XK_space;
+}
+
 }  // namespace
 
 // Get an ui::KeyboardCode from an X keyevent
@@ -492,7 +501,7 @@ 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) || IsAsciiControlOrSpaceKey(keysym)) {
     return KeyboardCodeFromXKeysym(keysym);
   }