[IME] Loads chromeos-xkb extension and add the extension based xkb keyboards in the chrome://settin…

chrome/browser/chromeos/input_method/input_method_util.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 "chrome/browser/chromeos/input_method/input_method_util.h"
 
 #include <algorithm>
 #include <functional>
 #include <map>
 #include <utility>
@@ skipping 323 matching lines @@
 bool InputMethodUtil::IsValidInputMethodId(
     const std::string& input_method_id) const {
   // We can't check the component extension is whilelisted or not here because
   // it might not be initialized.
   return GetInputMethodDescriptorFromId(input_method_id) != NULL ||
       extension_ime_util::IsComponentExtensionIME(input_method_id);
 }
 
 // static
 bool InputMethodUtil::IsKeyboardLayout(const std::string& input_method_id) {
-  const bool kCaseInsensitive = false;
-  return StartsWithASCII(input_method_id, "xkb:", kCaseInsensitive);
+  return StartsWithASCII(input_method_id, "xkb:", false) ||
+      extension_ime_util::IsKeyboardLayoutExtension(input_method_id);
 }
 
 std::string InputMethodUtil::GetLanguageCodeFromInputMethodId(
     const std::string& input_method_id) const {
   // The code should be compatible with one of codes used for UI languages,
   // defined in app/l10_util.cc.
   const char kDefaultLanguageCode[] = "en-US";
   std::map<std::string, std::string>::const_iterator iter
       = id_to_language_code_.find(input_method_id);
   return (iter == id_to_language_code_.end()) ?
@@ skipping 365 matching lines @@
     if (IsKeyboardLayout(input_method.id())) {
       xkb_id_to_descriptor_.insert(
           std::make_pair(input_method.GetPreferredKeyboardLayout(),
                          input_method));
     }
   }
 }
 
 }  // namespace input_method
 }  // namespace chromeos