Update Network & internet->Wi-Fi to use MasterSwitchPreference.

- Add a preference controller for Network & internet->Wi-Fi to control
  the preference toggling and summary update.
- Refactor WifiSettings and WifiEnabler to share code between the new
  wifi preference controller and the wifi setting.
- Refactor BluetoothSummaryHelper to have a common base class with the
  WifiSummaryHelper.
- Rename the summary helper to summary updater.

Bug: 34280769
Test: make RunSettingsRoboTests
Change-Id: I00ebfc161bcef89331bb41ba405ed8cb8232d248

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

@@ -24,6 +24,7 @@ import android.widget.CompoundButton;
 import android.widget.Switch;
 
 import com.android.settings.R;
+import com.android.settingslib.RestrictedLockUtils.EnforcedAdmin;
 
 /**
  * A custom preference that provides inline switch toggle. It has a mandatory field for title, and
@@ -76,7 +77,7 @@ public class MasterSwitchPreference extends Preference {
     }
 
     public boolean isChecked() {
-        return isEnabled() && mChecked;
+        return mSwitch != null && mSwitch.isEnabled() && mChecked;
     }
 
     public void setChecked(boolean checked) {
@@ -87,7 +88,7 @@ public class MasterSwitchPreference extends Preference {
     }
 
     public boolean isSwitchEnabled() {
-        return isEnabled() && mSwitch != null && mSwitch.isEnabled();
+        return mSwitch != null && mSwitch.isEnabled();
     }
 
     public void setSwitchEnabled(boolean enabled) {
@@ -96,6 +97,18 @@ public class MasterSwitchPreference extends Preference {
         }
     }
 
+    /**
+     * If admin is not null, disables the switch.
+     * Otherwise, keep it enabled.
+     */
+    public void setDisabledByAdmin(EnforcedAdmin admin) {
+        setSwitchEnabled(admin == null);
+    }
+
+    public Switch getSwitch() {
+        return mSwitch;
+    }
+
     private void init() {
         setWidgetLayoutResource(R.layout.preference_widget_master_switch);
     }