Add the ability to filter out extension IMEs from the language settings page.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index b751a79239db47959923710afd0bbf7c7f658bed..771608b69da012db071eb6e0853e98def4b268b5 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -564,6 +564,10 @@ const char kLanguagePreferredLanguages[] =
 // method IDs (ex. "pinyin,mozc").
 const char kLanguagePreloadEngines[] = "settings.language.preload_engines";
 
+// A List pref (comma-separated list) set to the extension IMEs to filter out.
+const char kLanguageFilteredExtensionImes[] =
+    "settings.language.filtered_extension_imes";
+
 // Boolean prefs for ibus-chewing Chinese input method.
 const char kLanguageChewingAutoShiftCur[] =
     "settings.language.chewing_auto_shift_cur";