Add default constructor in AddAppToHomescreenRule.

Provide option to pass app name in dynamic rule usage.

Bug: b/238675589

Test: local
Change-Id: Ibcaf589a92663135ef90d7bf6ebcbc9e72b179bb
diff --git a/libraries/health/rules/src/android/platform/test/rule/AddAppToHomescreenRule.java b/libraries/health/rules/src/android/platform/test/rule/AddAppToHomescreenRule.java
index 7265471..ac645c0 100644
--- a/libraries/health/rules/src/android/platform/test/rule/AddAppToHomescreenRule.java
+++ b/libraries/health/rules/src/android/platform/test/rule/AddAppToHomescreenRule.java
@@ -27,10 +27,14 @@
 public class AddAppToHomescreenRule extends TestWatcher {
     private static final String LOG_TAG = AddAppToHomescreenRule.class.getSimpleName();
     private static final String ADD_APP_TO_HOMESCREEN = "add-app-to-homescreen";
+    private static final String HOME_SCREEN_APP_NAME = "homescreen-app-name";
 
     private final LauncherInstrumentation mLauncher = new LauncherInstrumentation();
 
-    private final String mAppName;
+    private String mAppName;
+
+    public AddAppToHomescreenRule() {
+    }
 
     public AddAppToHomescreenRule(String appName) {
         mAppName = appName;
@@ -43,6 +47,11 @@
             return;
         }
 
+        String appName = getArguments().getString(HOME_SCREEN_APP_NAME, "");
+        if(appName != null && !appName.isEmpty()) {
+           mAppName = appName;
+        }
+
         // TODO(b/241957916): Use the #goHome method when it's synced to AOSP.
         mLauncher.pressHome();
         Workspace workspace = mLauncher.getWorkspace();