Android: Add logging for test dummy

This makes it easier to grep for TestDummyImpl results without requiring
physical access to the test device.

Bug: None
Change-Id: I35efca8d54a7fec9385262ca4bc6908b8692115d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1835706
Commit-Queue: Peter Wen <wnwen@chromium.org>
Auto-Submit: Peter Wen <wnwen@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702163}

chrome/android/features/test_dummy/internal/java/src/org/chromium/chrome/features/test_dummy/TestDummyImpl.java

@@ -56,12 +56,14 @@ public class TestDummyImpl implements TestDummy {
     }
 
     private void showDoneDialog(Activity activity, @TestCase int testCase, boolean pass) {
-        String message = "Test Case %d: " + (pass ? "pass" : "fail");
+        String message =
+                String.format(Locale.US, "Test Case %d: %s", testCase, pass ? "pass" : "fail");
         AlertDialog.Builder builder = new AlertDialog.Builder(activity);
         builder.setTitle("Test Dummy Result");
-        builder.setMessage(String.format(Locale.US, message, testCase));
+        builder.setMessage(message);
         builder.setCancelable(true);
         builder.create().show();
+        Log.i(TAG, message); // Useful for local testing and grepping.
     }
 
     private void executeJava(Activity activity) {