A quick fix for Issue 19421....

chrome/browser/autocomplete/autocomplete_edit_view_mac.mm

Index: chrome/browser/autocomplete/autocomplete_edit_view_mac.mm
===================================================================
--- chrome/browser/autocomplete/autocomplete_edit_view_mac.mm	(revision 23601)
+++ chrome/browser/autocomplete/autocomplete_edit_view_mac.mm	(working copy)
@@ -362,6 +362,18 @@
 }
 
 void AutocompleteEditViewMac::SetText(const std::wstring& display_text) {
+  // Exit if an input method is composing text.

[rohitrao (ping after 24h), 2009/08/18 21:42:35]

Is this guaranteed to be called again once the text is unmarked?

[Hironori Bono, 2009/08/19 05:23:38]

Yes. This function is called when this NSTextField control receives a
controlTextDidChange notification. Also, when the text is unmarked, Cocoa sends
a controlTextDidChange notification to this NSTextField control.
Thus, this function is called when the text is unmarked.

+  // NSTextView finishes an ongoing composition when updating the value of an
+  // NSTextField instance. This prevents inputting non-ASCII characters which
+  // need input methods, such as Latin characters, CJK characters, etc.
+  // To prevent updating this NSTextField value while an input method is
+  // composing text, we check whether or not the field editor for this control
+  // has marked text, text being composed by an input method, and return if
+  // the editor has marked text.
+  NSTextView* text_view = static_cast<NSTextView*>([field_ currentEditor]);
+  if (text_view && [text_view hasMarkedText])
+    return;
+
   NSString* ss = base::SysWideToNSString(display_text);
   NSMutableAttributedString* as =
       [[[NSMutableAttributedString alloc] initWithString:ss] autorelease];