Turn MtpDocumentsService foreground when devices are opend.

BUG=26047393

Change-Id: I70f69c5ddec500ed61d1a76fb9e2e296813b2a4e
diff --git a/packages/MtpDocumentsProvider/AndroidManifest.xml b/packages/MtpDocumentsProvider/AndroidManifest.xml
index 0172a4f..3861d78 100644
--- a/packages/MtpDocumentsProvider/AndroidManifest.xml
+++ b/packages/MtpDocumentsProvider/AndroidManifest.xml
@@ -15,17 +15,14 @@
                 <action android:name="android.content.action.DOCUMENTS_PROVIDER" />
             </intent-filter>
         </provider>
-        <activity android:name=".ReceiverActivity"
-                  android:theme="@android:style/Theme.NoDisplay"
-                  android:screenOrientation="locked"
-                  android:excludeFromRecents="true"
-                  android:enabled="false">
+        <service android:name=".MtpDocumentsService" />
+        <receiver android:name=".UsbIntentReceiver" android:exported="true">
             <intent-filter>
                 <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
+                <action android:name="android.hardware.usb.action.USB_DEVICE_DETACHED" />
             </intent-filter>
             <meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
-                       android:resource="@xml/device_filter" />
-        </activity>
-        <service android:name=".MtpDocumentsService"></service>
+                    android:resource="@xml/device_filter" />
+        </receiver>
     </application>
 </manifest>