Workaround: Wrap IBusText with ibus namespace.

chromeos/dbus/ibus/ibus_text.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 "chromeos/dbus/ibus/ibus_text.h"
 
 #include "base/logging.h"
 #include "chromeos/dbus/ibus/ibus_object.h"
 #include "dbus/message.h"
 
 namespace chromeos {
+// TODO(nona): Remove ibus namespace after complete libibus removal.
+namespace ibus {
 
 namespace {
 const uint32 kAttributeUnderline = 1;  // Indicates underline attribute.
 const uint32 kAttributeSelection = 2;  // Indicates background attribute.
 
 struct IBusAttribute {
   IBusAttribute() : type(0), value(0), start_index(0), end_index(0) {}
   uint32 type;
   uint32 value;
   uint32 start_index;
@@ skipping 159 matching lines @@
 std::vector<IBusText::SelectionAttribute>*
     IBusText::mutable_selection_attributes() {
   return &selection_attributes_;
 }
 
 const std::vector<IBusText::SelectionAttribute>&
     IBusText::selection_attributes() const {
   return selection_attributes_;
 }
 
+}  // namespace ibus
 }  // namespace chromeos