Move Java Blimp shell code to app subpackage

blimp/client/app/android/java/src/org/chromium/blimp/app/preferences/PreferencesUtil.java

 // Copyright 2016 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.blimp.preferences;
+package org.chromium.blimp.app.preferences;
 
 import android.content.Context;
 
 import org.chromium.base.ContextUtils;
-import org.chromium.blimp.R;
+import org.chromium.blimp.app.R;
 
 /**
  * Provides helper methods for storing and retrieving values in android shared preferences.
  */
 public class PreferencesUtil {
     /**
      * Preference that stores the last used assigner URL.
      */
     private static final String PREF_LAST_USED_ASSIGNER = "last_known_assigner";
     private static final String DEFAULT_EMPTY_STRING = "";
 
     /**
      * Finds the assigner to be used from user's last preference. If the app is being used for the
      * first time, the first entry from the assigner array would be used.
      * @return assigner to use.
      */
     public static String findAssignerUrl(Context context) {
         String lastAssigner = getLastUsedAssigner(context);
         if (lastAssigner.isEmpty()) {
-            String[] assignerUrls = context.getResources().getStringArray(
-                    R.array.blimp_assigner_urls);
+            String[] assignerUrls =
+                    context.getResources().getStringArray(R.array.blimp_assigner_urls);
             assert assignerUrls != null && assignerUrls.length > 0;
             lastAssigner = assignerUrls[0];
             setLastUsedAssigner(context, lastAssigner);
         }
         return lastAssigner;
     }
 
     /**
      * Reads the last used assigner from shared preference.
      * @param context The current Android context
@@ skipping 25 matching lines @@
     /**
      * Writes the given string into shared preference.
      * @param context The current Android context
      * @param key The name of the preference to modify
      * @param value The new value for the preference
      */
     private static void writeString(Context context, String key, String value) {
         ContextUtils.getAppSharedPreferences().edit().putString(key, value).apply();
     }
 }