Allow autoplay unmuted for WebAPK in the manifest scope

chrome/android/java/templates/MonochromeApplication.template

 // 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 {{package}};
 
 import android.content.Context;
 
 import com.android.webview.chromium.MonochromeLibraryPreloader;
 
@@ skipping 16 matching lines @@
         return mChildProcessCreationParams;
     }
 
     @Override
     public void onCreate() {
         super.onCreate();
         LibraryLoader.setNativeLibraryPreloader(new MonochromeLibraryPreloader());
         // ChildProcessCreationParams is only needed for browser process, though it is
         // created and set in all processes.
         mChildProcessCreationParams = new ChildProcessCreationParams(getPackageName(),
-                true /* isExternalService */, LibraryProcessType.PROCESS_CHILD);
+                true /* isExternalService */, LibraryProcessType.PROCESS_CHILD,
+                null /* additionalCommandLine */);
         ChildProcessCreationParams.set(mChildProcessCreationParams);
     }
 }