Fix a bug in show surface updates

- fix a bug that caused the master switch to unintentionally turn on
 the show surface updates preference

Bug: 34203528
Test: make RunSettingsRoboTests -j40
Change-Id: I307a801aa1a7c1606b3f5d55a0d1f2dbf1d60416

src/com/android/settings/development/ShowSurfaceUpdatesPreferenceController.java

@@ -86,8 +86,12 @@ public class ShowSurfaceUpdatesPreferenceController extends DeveloperOptionsPref
 
     @Override
     protected void onDeveloperOptionsSwitchDisabled() {
-        writeShowUpdatesSetting(false);
-        mPreference.setChecked(false);
+        if (mPreference.isChecked()) {
+            // Writing false to the preference when the setting is already off will have a
+            // side effect of turning on the preference that we wish to avoid
+            writeShowUpdatesSetting(false);
+            mPreference.setChecked(false);
+        }
         mPreference.setEnabled(false);
     }