Add ability to open up "Open by default" page directly via intent.

Bug: 74010481
Test: Manually check; sending an Intent with package:// scheme works, if
originated from app of same cert.
Change-Id: I5700e495d259d0197421f40594861bc43e3c154c

src/com/android/settings/applications/InstalledAppOpenByDefaultPage.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.applications;
+
+import android.content.Intent;
+
+import com.android.settings.SettingsActivity;
+
+public class InstalledAppOpenByDefaultPage extends SettingsActivity {
+
+    @Override
+    public Intent getIntent() {
+        Intent modIntent = new Intent(super.getIntent());
+        modIntent.putExtra(EXTRA_SHOW_FRAGMENT, AppLaunchSettings.class.getName());
+        return modIntent;
+    }
+
+    @Override
+    protected boolean isValidFragment(String fragmentName) {
+        return AppLaunchSettings.class.getName().equals(fragmentName);
+    }
+}