Register ENABLED_INPUT_METHODS to SettingsObserver

Bug: 3415292

- Registration is required for catching current IME or subtype is disabled

Change-Id: Ia95f16df5bd725c05b4f5085f975d235b88d4b6e

services/java/com/android/server/InputMethodManagerService.java

@@ -329,6 +329,8 @@ public class InputMethodManagerService extends IInputMethodManager.Stub
             ContentResolver resolver = mContext.getContentResolver();
             resolver.registerContentObserver(Settings.Secure.getUriFor(
                     Settings.Secure.DEFAULT_INPUT_METHOD), false, this);
+            resolver.registerContentObserver(Settings.Secure.getUriFor(
+                    Settings.Secure.ENABLED_INPUT_METHODS), false, this);
             resolver.registerContentObserver(Settings.Secure.getUriFor(
                     Settings.Secure.SELECTED_INPUT_METHOD_SUBTYPE), false, this);
         }