AAPT2: Fix issue where exported symbols (@+id/*) were not exported

Test: make AaptTestAppOne
Change-Id: If3218c880e83c2cfaf535a099db38504471be676
diff --git a/tools/aapt2/integration-tests/StaticLibTest/App/AndroidManifest.xml b/tools/aapt2/integration-tests/StaticLibTest/App/AndroidManifest.xml
index a5f202d..c8f4bda 100644
--- a/tools/aapt2/integration-tests/StaticLibTest/App/AndroidManifest.xml
+++ b/tools/aapt2/integration-tests/StaticLibTest/App/AndroidManifest.xml
@@ -21,7 +21,7 @@
     <uses-permission-sdk-23 android:name="android.permission.TEST" android:maxSdkVersion="22" />
 
     <application>
-        <activity android:name=".MyActivity">
+        <activity android:name=".MyActivity" android:id="@+id/sample_generated_id">
             <layout android:defaultHeight="500dp"
                 android:defaultWidth="600dp" />
         </activity>