Do not show security warning for the system IMEs

Bug: 6587127
Change-Id: I00584fb81cf5b39806c30a801b215a0e9a1e9399
diff --git a/src/com/android/settings/inputmethod/InputMethodPreference.java b/src/com/android/settings/inputmethod/InputMethodPreference.java
index c736b2f5..f555d21 100644
--- a/src/com/android/settings/inputmethod/InputMethodPreference.java
+++ b/src/com/android/settings/inputmethod/InputMethodPreference.java
@@ -53,6 +53,7 @@
     private final InputMethodManager mImm;
     private final Intent mSettingsIntent;
     private final boolean mAlwaysChecked;
+    private final boolean mIsSystemIme;
 
     private AlertDialog mDialog = null;
     private ImageView mInputMethodSettingsButton;
@@ -69,7 +70,7 @@
             if (isChecked()) {
                 setChecked(false, true /* save */);
             } else {
-                if (mAlwaysChecked) {
+                if (mIsSystemIme) {
                     setChecked(true, true /* save */);
                 } else {
                     showSecurityWarnDialog(mImi, InputMethodPreference.this);
@@ -90,6 +91,7 @@
         updateSummary();
         mAlwaysChecked = InputMethodAndSubtypeUtil.isAlwaysCheckedIme(
                 imi, fragment.getActivity(), imiCount);
+        mIsSystemIme = InputMethodAndSubtypeUtil.isSystemIme(imi);
         if (mAlwaysChecked) {
             setEnabled(false);
         }