webapps: Add cleanup task when opening up WebappActivity to clean old web apps

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.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 android.content.Context;
 import android.content.SharedPreferences;
 import android.graphics.Bitmap;
 import android.os.AsyncTask;
@@ skipping 113 matching lines @@
     }
 
     /*
      * Update the information associated with the web app with the specified data.
      * @param splashScreenImage The image which should be shown on the splash screen of the web app.
      */
     public void updateSplashScreenImage(Bitmap splashScreenImage) {
         new UpdateTask(splashScreenImage).execute();
     }
 
-    /** Package private for use by WebappRegistry */
     void updateLastUsedTime() {
         assert !ThreadUtils.runningOnUiThread();
         mPreferences.edit().putLong(KEY_LAST_USED, System.currentTimeMillis()).commit();
     }
 
-    private long getLastUsedTime() {
+    long getLastUsedTime() {
         assert !ThreadUtils.runningOnUiThread();
         return mPreferences.getLong(KEY_LAST_USED, INVALID_LAST_USED);
     }
 
     private Map<String, ?> getAllData() {
         return mPreferences.getAll();
     }
 
     /**
      * Called after data has been retrieved from storage.
@@ skipping 48 matching lines @@
 
         @Override
         protected Void doInBackground(Void... nothing) {
             mPreferences.edit()
                     .putString(KEY_SPLASH_ICON, ShortcutHelper.encodeBitmapAsString(mSplashImage))
                     .commit();
             return null;
         }
     }
 }