[Device Service] Decouple NFC implementation from //content

device/nfc/android/java/src/org/chromium/device/nfc/NfcImpl.java

Index: device/nfc/android/java/src/org/chromium/device/nfc/NfcImpl.java
diff --git a/device/nfc/android/java/src/org/chromium/device/nfc/NfcImpl.java b/device/nfc/android/java/src/org/chromium/device/nfc/NfcImpl.java
index a2c5380a1111c9f15a45ad1eb12cffc07ecaa298..718bdcfb5a5167077518d9d4ebf8e3aa4e356dcc 100644
--- a/device/nfc/android/java/src/org/chromium/device/nfc/NfcImpl.java
+++ b/device/nfc/android/java/src/org/chromium/device/nfc/NfcImpl.java
@@ -21,6 +21,7 @@ import android.os.Handler;
 import android.os.Process;
 import android.util.SparseArray;
 
+import org.chromium.base.Callback;
 import org.chromium.base.Log;
 import org.chromium.device.nfc.mojom.Nfc;
 import org.chromium.device.nfc.mojom.NfcClient;
@@ -46,6 +47,10 @@ import java.util.List;
 public class NfcImpl implements Nfc {
     private static final String TAG = "NfcImpl";
 
+    private final int mHostId;
+
+    private final NfcDelegate mDelegate;
+
     /**
      * Used to get instance of NFC adapter, @see android.nfc.NfcManager
      */
@@ -114,10 +119,20 @@ public class NfcImpl implements Nfc {
      */
     private Runnable mPushTimeoutRunnable;
 
-    public NfcImpl(Context context) {
+    public NfcImpl(Context context, int hostId, NfcDelegate delegate) {
+        mHostId = hostId;
+        mDelegate = delegate;
         int permission =
                 context.checkPermission(Manifest.permission.NFC, Process.myPid(), Process.myUid());
         mHasPermission = permission == PackageManager.PERMISSION_GRANTED;
+        Callback<Activity> onActivityUpdatedCallback = new Callback<Activity>() {
+            @Override
+            public void onResult(Activity activity) {
+                setActivity(activity);
+            }
+        };
+
+        mDelegate.trackActivityForHost(mHostId, onActivityUpdatedCallback);
 
         if (!mHasPermission || Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
             Log.w(TAG, "NFC operations are not permitted.");
@@ -293,6 +308,7 @@ public class NfcImpl implements Nfc {
 
     @Override
     public void close() {
+        mDelegate.stopTrackingActivityForHost(mHostId);
         disableReaderMode();
     }