Provide an API to make USSD calls and read the responses.

Test: will be added in a subsequent CL.
Bug: 30973910
Change-Id: Ie92441b6435775d9b6d74f9a0777064d9839d6dc
diff --git a/testapps/AndroidManifest.xml b/testapps/AndroidManifest.xml
index 7327e43..c1eb258 100644
--- a/testapps/AndroidManifest.xml
+++ b/testapps/AndroidManifest.xml
@@ -146,5 +146,15 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+
+        <activity android:name="com.android.server.telecom.testapps.TestUssdActivity"
+                android:label="@string/UssdUiAppLabel"
+                android:launchMode="singleInstance">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
     </application>
 </manifest>