Workaround: Wrap IBusText with ibus namespace.

chromeos/dbus/ibus/ibus_text.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 CHROMEOS_DBUS_IBUS_IBUS_TEXT_H_
 #define CHROMEOS_DBUS_IBUS_IBUS_TEXT_H_
 
 #include <string>
 #include <vector>
 #include "base/basictypes.h"
 #include "chromeos/chromeos_export.h"
 
 namespace dbus {
 class MessageWriter;
 class MessageReader;
 }  // dbus
 
 namespace chromeos {
+// TODO(nona): Remove ibus namespace after complete libibus removal.
+namespace ibus {
 
 // The IBusText is one of IBusObjects and it contains IBusAttrList object which
 // contains array of IBusAttribute object. The overview of each data strucutres
 // is as follows:
 //
 // DATA STRUCTURE OVERVIEW:
 //
 // IBusAttribute: (signature is "uuuu")
 // variant  struct {
 //     string "IBusAttribute"
@@ skipping 108 matching lines @@
   std::vector<SelectionAttribute>* mutable_selection_attributes();
 
  private:
   std::string text_;
   std::vector<UnderlineAttribute> underline_attributes_;
   std::vector<SelectionAttribute> selection_attributes_;
 
   DISALLOW_COPY_AND_ASSIGN(IBusText);
 };
 
+}  // namespace ibus
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_IBUS_IBUS_TEXT_H_