Add a flag in WebAPK's proto when the Web App Manifest is no longer available.

chrome/android/junit/src/org/chromium/chrome/browser/webapps/WebApkUpdateManagerTest.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.chrome.browser.webapps;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
@@ skipping 112 matching lines @@
             return mDestroyedManifestUpgradeDetector;
         }
 
         @Override
         protected ManifestUpgradeDetector buildManifestUpgradeDetector(Tab tab, WebApkInfo info) {
             mUpgradeDetector = new TestManifestUpgradeDetector(tab, info, this);
             return mUpgradeDetector;
         }
 
         @Override
-        protected void updateAsync(WebApkInfo info, String bestIconUrl) {
+        protected void updateAsync(WebApkInfo info, String bestIconUrl, boolean staleManifest) {
             ++mNumUpdatesRequested;
             mUpdateName = info.name();
         }
 
         @Override
         protected void destroyUpgradeDetector() {
             mUpgradeDetector = null;
             mDestroyedManifestUpgradeDetector = true;
         }
 
@@ skipping 325 matching lines @@
         updateIfNeeded(updateManager);
         updateManager.onFinishedFetchingWebManifestForInitialUrl(false, null, null);
         updateManager.onGotManifestData(false, fetchedWebApkInfo(), null);
         assertFalse(updateManager.updateRequested());
 
         // We got the Web Manifest. The {@link ManifestUpgradeDetector} should be destroyed to stop
         // it from fetching the Web Manifest for subsequent page loads.
         assertTrue(updateManager.destroyedManifestUpgradeDetector());
     }
 }