Exercise default phone application request in TestDialer

Change-Id: I87689bf601c5c09c1c80def868f336ee056010a3
diff --git a/tests/src/com/android/telecomm/testapps/TestDialerActivity.java b/tests/src/com/android/telecomm/testapps/TestDialerActivity.java
index 405bca5..5f3c999 100644
--- a/tests/src/com/android/telecomm/testapps/TestDialerActivity.java
+++ b/tests/src/com/android/telecomm/testapps/TestDialerActivity.java
@@ -3,6 +3,7 @@
 import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
+import android.telecomm.TelecommConstants;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.EditText;
@@ -47,7 +48,9 @@
     }
 
     private void setDefault() {
-        // TODO: Send a request to become the default dialer application
+        final Intent intent = new Intent(TelecommConstants.ACTION_CHANGE_DEFAULT_PHONE);
+        intent.putExtra(TelecommConstants.EXTRA_PACKAGE_NAME, this.getBasePackageName());
+        startActivity(intent);
     }
 
     private void placeCall() {