Do not try to get a display name from an input method ID which starts with "_ext_ime".

chrome/browser/chromeos/input_method/input_method_util.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 CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_UTIL_H_
 #define CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_UTIL_H_
 #pragma once
 
 #include <cstddef>
 #include <map>
@@ skipping 113 matching lines @@
   // This function should be called when Chrome's application locale is
   // changed, so that the internal maps of this library is reloaded.
   void OnLocaleChanged();
 
   // Sets an input method ID of the hardware keyboard for testing.
   void SetHardwareInputMethodIdForTesting(const std::string& input_method_id);
 
   // Returns true if the given input method id is for a keyboard layout.
   static bool IsKeyboardLayout(const std::string& input_method_id);
 
+  // Returns true if the given input method id is for an extension input method.
+  static bool IsExtensionInputMethod(const std::string& input_method_id);
+
   // Converts a language code to a language display name, using the
   // current application locale. MaybeRewriteLanguageName() is called
   // internally.
   // Examples: "fi"    => "Finnish"
   //           "en-US" => "English (United States)"
   static string16 GetLanguageDisplayNameFromCode(
       const std::string& language_code);
 
   // Converts a language code to a language native display name.
   // MaybeRewriteLanguageName() is called internally.
@@ skipping 48 matching lines @@
   typedef base::hash_map<std::string, int> HashType;
   HashType english_to_resource_id_;
 
   std::string hardware_input_method_id_for_testing_;
 };
 
 }  // namespace input_method
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_UTIL_H_