Pass JavaRef to Java methods in device/bluetooth.

device/bluetooth/bluetooth_adapter_android.cc

Index: device/bluetooth/bluetooth_adapter_android.cc
diff --git a/device/bluetooth/bluetooth_adapter_android.cc b/device/bluetooth/bluetooth_adapter_android.cc
index 958f3655b8929e04066dc0f31bc87b8555f8abbb..aa92604c50afa04cfa7de001ac933e9e94d222a4 100644
--- a/device/bluetooth/bluetooth_adapter_android.cc
+++ b/device/bluetooth/bluetooth_adapter_android.cc
@@ -24,6 +24,7 @@ using base::android::AttachCurrentThread;
 using base::android::ConvertJavaStringToUTF8;
 using base::android::AppendJavaStringArrayToStringVector;
 using base::android::JavaParamRef;
+using base::android::JavaRef;
 
 namespace {
 // The poll interval in ms when there is no active discovery. This
@@ -42,12 +43,13 @@ namespace device {
 base::WeakPtr<BluetoothAdapter> BluetoothAdapter::CreateAdapter(
     const InitCallback& init_callback) {
   return BluetoothAdapterAndroid::Create(
-      BluetoothAdapterWrapper_CreateWithDefaultAdapter().obj());
+      BluetoothAdapterWrapper_CreateWithDefaultAdapter());
 }
 
 // static
 base::WeakPtr<BluetoothAdapterAndroid> BluetoothAdapterAndroid::Create(
-    jobject bluetooth_adapter_wrapper) {  // Java Type: bluetoothAdapterWrapper
+    const JavaRef<jobject>&
+        bluetooth_adapter_wrapper) {  // Java Type: bluetoothAdapterWrapper
   BluetoothAdapterAndroid* adapter = new BluetoothAdapterAndroid();
 
   adapter->j_adapter_.Reset(Java_ChromeBluetoothAdapter_create(