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

tests/robotests/src/com/android/settings/widget/MasterSwitchPreferenceTest.java

@@ -27,6 +27,7 @@ import android.widget.Switch;
 import com.android.settings.R;
 import com.android.settings.SettingsRobolectricTestRunner;
 import com.android.settings.TestConfig;
+import com.android.settingslib.RestrictedLockUtils.EnforcedAdmin;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -118,4 +119,30 @@ public class MasterSwitchPreferenceTest {
         toggle.setChecked(false);
         verify(listener).onPreferenceChange(preference, false);
     }
+
+    @Test
+    public void setDisabledByAdmin_hasEnforcedAdmin_shouldDisableButton() {
+        final MasterSwitchPreference preference = new MasterSwitchPreference(mContext);
+        final PreferenceViewHolder holder = new PreferenceViewHolder(
+            LayoutInflater.from(mContext).inflate(R.layout.preference_widget_master_switch, null));
+        final Switch toggle = (Switch) holder.itemView.findViewById(R.id.switchWidget);
+        toggle.setEnabled(true);
+        preference.onBindViewHolder(holder);
+
+        preference.setDisabledByAdmin(mock(EnforcedAdmin.class));
+        assertThat(toggle.isEnabled()).isFalse();
+    }
+
+    @Test
+    public void setDisabledByAdmin_noEnforcedAdmin_shouldEnaableButton() {
+        final MasterSwitchPreference preference = new MasterSwitchPreference(mContext);
+        final PreferenceViewHolder holder = new PreferenceViewHolder(
+            LayoutInflater.from(mContext).inflate(R.layout.preference_widget_master_switch, null));
+        final Switch toggle = (Switch) holder.itemView.findViewById(R.id.switchWidget);
+        toggle.setEnabled(false);
+        preference.onBindViewHolder(holder);
+
+        preference.setDisabledByAdmin(null);
+        assertThat(toggle.isEnabled()).isTrue();
+    }
 }