Upstream: Initialize ChromeWebApkHost in WebappLaunchActivity.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.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.app.Activity;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Build;
@@ skipping 46 matching lines @@
         String webApkPackageName = webappInfo.webApkPackageName();
         int webappSource = webappInfo.source();
 
         if (webappId != null && webappUrl != null) {
             Intent launchIntent = null;
 
             // Permit the launch to a standalone web app frame if any of the following are true:
             // - the request was for a WebAPK that is valid;
             // - the MAC is present and valid for the homescreen shortcut to be opened;
             // - the intent was sent by Chrome.
+            if (CommandLine.getInstance().hasSwitch(ChromeSwitches.ENABLE_WEBAPK)) {
+                ChromeWebApkHost.init();
+            }
             boolean isValidWebApk = isValidWebApk(webApkPackageName, webappUrl);
 
             if (isValidWebApk
                     || isValidMacForUrl(webappUrl, IntentUtils.safeGetStringExtra(
                             intent, ShortcutHelper.EXTRA_MAC))
                     || wasIntentFromChrome(intent)) {
                 LaunchMetrics.recordHomeScreenLaunchIntoStandaloneActivity(webappUrl, webappSource);
                 launchIntent = createWebappLaunchIntent(webappInfo, isValidWebApk);
             } else {
                 Log.e(TAG, "Shortcut (%s) opened in Chrome.", webappUrl);
@@ skipping 108 matching lines @@
             Log.d(TAG, "%s is not valid WebAPK", webApkPackage);
             return false;
         }
         if (!webApkPackage.equals(WebApkValidator.queryWebApkPackage(this, url))) {
             Log.d(TAG, "%s is not within scope of %s WebAPK", url, webApkPackage);
             return false;
         }
         return true;
     }
 }