Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

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.Color;
 import android.graphics.drawable.Drawable;
@@ skipping 120 matching lines @@
         ScreenOrientationProvider.lockOrientation((byte) mWebappInfo.orientation(), this);
         super.preInflationStartup();
     }
 
     @Override
     public void finishNativeInitialization() {
         if (!mWebappInfo.isInitialized()) finish();
         super.finishNativeInitialization();
         initializeUI(getSavedInstanceState());
         mIsInitialized = true;
+        checkUpdates();

[pkotwicz, 2016/07/19 18:02:38]

Can WebApkActivity override finishNativeInitialization() and call checkUpdates()
instead?

[Yaron, 2016/07/20 02:27:58]

+1

[Xi Han, 2016/07/20 18:55:00]

Done.

     }
 
+    protected void checkUpdates() {}
+
     @Override
     protected void onSaveInstanceState(Bundle outState) {
         super.onSaveInstanceState(outState);
         if (getActivityTab() != null) {
             outState.putInt(BUNDLE_TAB_ID, getActivityTab().getId());
             outState.putString(BUNDLE_TAB_URL, getActivityTab().getUrl());
         }
     }
 
     @Override
@@ skipping 424 matching lines @@
         return new WebappDelegateFactory(this);
     }
 
     // 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;
     }
 }