Update NotificationChannelSettings Preferences in place to prevent re-layout.

(cherry picked from commit b409b64045)

Fixes: 110093185
Test: ChannelListPreferenceControllerTest
Change-Id: If6acf305c44085e502a3304ea57e409ce049b40f
Merged-In: If6acf305c44085e502a3304ea57e409ce049b40f

src/com/android/settings/widget/MasterSwitchPreference.java

@@ -23,6 +23,8 @@ import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.Switch;
 
+import androidx.annotation.Keep;
+import androidx.annotation.Nullable;
 import androidx.preference.PreferenceViewHolder;
 
 import com.android.settings.R;
@@ -101,6 +103,16 @@ public class MasterSwitchPreference extends RestrictedPreference {
         return mSwitch != null && mChecked;
     }
 
+    /**
+     * Used to validate the state of mChecked and mCheckedSet when testing, without requiring
+     * that a ViewHolder be bound to the object.
+     */
+    @Keep
+    @Nullable
+    public Boolean getCheckedState() {
+        return mCheckedSet ? mChecked : null;
+    }
+
     public void setChecked(boolean checked) {
         // Always set checked the first time; don't assume the field's default of false.
         final boolean changed = mChecked != checked;