Convert Magnify controller to TogglePrefController

Convert below to TogglePreferenceController:
MagnificationNavbarPreferenceController
(Magnify with Button)
MagnificationGesturesPreferenceController
(Magnify with triple-tap)

The two controllers share the same fragment,
Add static method for set/get state in fragment,
And use them in controllers and fragment.

Change-Id: I2bdbdb36be71e1a3ffb557abc5a6115d48de53cf
Fixes: 67997698
Fixes: 67997726
Test: make RunSettingsRoboTests

src/com/android/settings/gestures/GesturePreferenceController.java

@@ -59,9 +59,6 @@ public abstract class GesturePreferenceController extends TogglePreferenceContro
     public void updateState(Preference preference) {
         super.updateState(preference);
         if (preference != null) {
-            if (!(preference instanceof TwoStatePreference)) {
-                preference.setSummary(getSummary());
-            }
             // Different meanings of "Enabled" for the Preference and Controller.
             preference.setEnabled(canHandleClicks());
         }