Provide an overload to WebView::create that does not require a WebViewClient.

third_party/WebKit/Source/web/WebViewImpl.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 86 matching lines @@
 class WebViewScheduler;
 
 class WEB_EXPORT WebViewImpl final
     : NON_EXPORTED_BASE(public WebView),
       public RefCounted<WebViewImpl>,
       NON_EXPORTED_BASE(public WebGestureCurveTarget),
       public PageWidgetEventHandler,
       public WebScheduler::InterventionReporter,
       public WebViewScheduler::WebViewSchedulerSettings {
  public:
+  static WebViewImpl* create(WebPageVisibilityState);
   static WebViewImpl* create(WebViewClient*, WebPageVisibilityState);
   static HashSet<WebViewImpl*>& allInstances();
 
   class UserGestureNotifier {
    public:
     // If a UserGestureIndicator is created for a user gesture since the last
     // page load and the WebViewImpl's |m_userGestureObserved| is false, the
     // UserGestureNotifier will notify the client and set
     // |m_userGestureObserved| to true.
     UserGestureNotifier(WebViewImpl*);
@@ skipping 625 matching lines @@
   Persistent<ResizeViewportAnchor> m_resizeViewportAnchor;
 };
 
 // We have no ways to check if the specified WebView is an instance of
 // WebViewImpl because WebViewImpl is the only implementation of WebView.
 DEFINE_TYPE_CASTS(WebViewImpl, WebView, webView, true, true);
 
 }  // namespace blink
 
 #endif