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

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.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.Intent;
 import android.graphics.Bitmap;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
@@ skipping 35 matching lines @@
  * Displays a webapp in a nearly UI-less Chrome (InfoBars still appear).
  */
 public class WebappActivity extends FullScreenActivity {
     public static final String WEBAPP_SCHEME = "webapp";
 
     private static final String TAG = "WebappActivity";
     private static final long MS_BEFORE_NAVIGATING_BACK_FROM_INTERSTITIAL = 1000;
 
     private final WebappInfo mWebappInfo;
     private AsyncTask<Void, Void, Void> mCleanupTask;
+    private boolean mOldWebappCleanupStarted;
 
     private WebContentsObserver mWebContentsObserver;
 
     private ViewGroup mSplashScreen;
     private WebappUrlBar mUrlBar;
 
     private boolean mIsInitialized;
     private Integer mBrandColor;
 
     /**
@@ skipping 83 matching lines @@
     @Override
     public void onResume() {
         if (!isFinishing()) {
             if (getIntent() != null) {
                 // Avoid situations where Android starts two Activities with the same data.
                 DocumentUtils.finishOtherTasksWithData(getIntent().getData(), getTaskId());
             }
             updateTaskDescription();
         }
         super.onResume();
+
+        // Kick off the old web app cleanup (if we haven't already) now that we have queued the
+        // current web app's storage to be opened.
+        if (!mOldWebappCleanupStarted) {
+            WebappRegistry.unregisterOldWebapps(this, System.currentTimeMillis());
+            mOldWebappCleanupStarted = true;
+        }
     }
 
     @Override
     protected int getControlContainerLayoutId() {
         return R.layout.webapp_control_container;
     }
 
     @Override
     public void postInflationStartup() {
         initializeSplashScreen();
@@ skipping 242 matching lines @@
         return visible;
     }
 
     // We're temporarily disable CS on webapp since there are some issues. (http://crbug.com/471950)
     // TODO(changwan): re-enable it once the issues are resolved.
     @Override
     protected boolean isContextualSearchAllowed() {
         return false;
     }
 }