Revert of [Reland] Refactor WebappRegistry into a singleton instance.

chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappActivityTestBase.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.webapps;
 
 import static org.chromium.base.test.util.ScalableTimeout.scaleTimeout;
 
 import android.content.Intent;
 import android.net.Uri;
@@ skipping 77 matching lines @@
         return intent;
     }
 
     @Override
     protected void setUp() throws Exception {
         super.setUp();
 
         // Register the webapp so when the data storage is opened, the test doesn't crash. There is
         // no race condition with the retrieval as AsyncTasks are run sequentially on the background
         // thread.
-        WebappRegistry.refreshSharedPrefsForTesting();
-        WebappRegistry.getInstance().register(
+        WebappRegistry.registerWebapp(
                 WEBAPP_ID, new WebappRegistry.FetchWebappDataStorageCallback() {
                     @Override
                     public void onWebappDataStorageRetrieved(WebappDataStorage storage) {
                         storage.updateFromShortcutIntent(createIntent());
                     }
                 });
     }
 
     /**
      * Starts up the WebappActivity and sets up the test observer.
@@ skipping 106 matching lines @@
             fail();
         }
 
         ViewGroup splashScreen = getActivity().getSplashScreenForTests();
         if (splashScreen == null) {
             fail("No splash screen available.");
         }
         return splashScreen;
     }
 }