Add ReceiverActivity to MtpDocumentsProvider.

To show the application chooser for the UsbManager.ACTION_USB_DEVICE_ATTACHED
intent, the intent should be received by activity. The activity has NoDisplay
theme and immediately terminate after routing intent to MtpDocumentsService.

BUG=20274999

Change-Id: I2080ea433b1657dd68640681664adbf92d1d30e9
diff --git a/packages/MtpDocumentsProvider/AndroidManifest.xml b/packages/MtpDocumentsProvider/AndroidManifest.xml
index c1848c7..0172a4f 100644
--- a/packages/MtpDocumentsProvider/AndroidManifest.xml
+++ b/packages/MtpDocumentsProvider/AndroidManifest.xml
@@ -15,6 +15,17 @@
                 <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">
+            <intent-filter>
+                <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
+            </intent-filter>
+            <meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
+                       android:resource="@xml/device_filter" />
+        </activity>
         <service android:name=".MtpDocumentsService"></service>
     </application>
 </manifest>