Add error handle for device that not support Bluetooth

- Add LocalBluetoothManager null check for device that
  not support Bluetooth
- Add test to verify when LocalBluetoothManager is null
  will not crash

Bug: 110712414
Test: make -j42 RunSettingsRoboTests
Change-Id: Ib506a0206cfcfdfec60bdfcf9a1944338a7ab729

tests/robotests/src/com/android/settings/connecteddevice/AvailableMediaDeviceGroupControllerTest.java

@@ -197,4 +197,20 @@ public class AvailableMediaDeviceGroupControllerTest {
         assertThat(mPreferenceGroup.getTitle()).isEqualTo(
                 mContext.getText(R.string.connected_device_available_media_title));
     }
+
+    @Test
+    public void onStart_localBluetoothManagerNull_shouldNotCrash() {
+        mAvailableMediaDeviceGroupController.mLocalBluetoothManager = null;
+
+        // Shouldn't crash
+        mAvailableMediaDeviceGroupController.onStart();
+    }
+
+    @Test
+    public void onStop_localBluetoothManagerNull_shouldNotCrash() {
+        mAvailableMediaDeviceGroupController.mLocalBluetoothManager = null;
+
+        // Shouldn't crash
+        mAvailableMediaDeviceGroupController.onStop();
+    }
 }

tests/robotests/src/com/android/settings/connecteddevice/DiscoverableFooterPreferenceControllerTest.java

@@ -178,4 +178,22 @@ public class DiscoverableFooterPreferenceControllerTest {
         }
         return registeredBroadcastReceivers;
     }
+
+    @Test
+    public void onResume_localBluetoothManagerNull_shouldNotCrash() {
+        mDiscoverableFooterPreferenceController.mLocalManager = null;
+        mDiscoverableFooterPreferenceController.init(mFooterPreferenceMixin, mPreference, null);
+
+        // Shouldn't crash
+        mDiscoverableFooterPreferenceController.onResume();
+    }
+
+    @Test
+    public void onPause_localBluetoothManagerNull_shouldNotCrash() {
+        mDiscoverableFooterPreferenceController.mLocalManager = null;
+        mDiscoverableFooterPreferenceController.init(mFooterPreferenceMixin, mPreference, null);
+
+        // Shouldn't crash
+        mDiscoverableFooterPreferenceController.onPause();
+    }
 }