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

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 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 253 matching lines @@
       return;
     FloatRect rect(0, 0, size.width, size.height);
     DrawingRecorder drawingRecorder(graphicsContext, pageOverlay,
                                     DisplayItem::kPageOverlay, rect);
     graphicsContext.fillRect(rect, m_color);
   }
 
   WebColor m_color;
 };
 
+class DetachedWebViewClient : public WebViewClient {
+ public:
+  virtual ~DetachedWebViewClient() {}
+};
+
 }  // namespace
 
 // WebView ----------------------------------------------------------------
 
+WebView* WebView::create(WebPageVisibilityState visibilityState) {
+  return WebViewImpl::create(visibilityState);
+}
+
 WebView* WebView::create(WebViewClient* client,
                          WebPageVisibilityState visibilityState) {
+  DCHECK(client) << "A valid WebViewClient must be supplied.";
   // Pass the WebViewImpl's self-reference to the caller.
   return WebViewImpl::create(client, visibilityState);
 }
 
+WebViewImpl* WebViewImpl::create(WebPageVisibilityState visibilityState) {
+  DEFINE_STATIC_LOCAL(DetachedWebViewClient, detachedWebViewClient, ());
+  return adoptRef(new WebViewImpl(&detachedWebViewClient, visibilityState))
+      .leakRef();
+}
+
 WebViewImpl* WebViewImpl::create(WebViewClient* client,
                                  WebPageVisibilityState visibilityState) {
+  DCHECK(client) << "A valid WebViewClient must be supplied.";
   // Pass the WebViewImpl's self-reference to the caller.
   return adoptRef(new WebViewImpl(client, visibilityState)).leakRef();
 }
 
 void WebView::setUseExternalPopupMenus(bool useExternalPopupMenus) {
   shouldUseExternalPopupMenus = useExternalPopupMenus;
 }
 
 void WebView::updateVisitedLinkState(unsigned long long linkHash) {
   Page::visitedStateChanged(linkHash);
@@ skipping 3884 matching lines @@
   if (focusedFrame->localFrameRoot() != mainFrameImpl()->frame())
     return nullptr;
   return focusedFrame;
 }
 
 LocalFrame* WebViewImpl::focusedLocalFrameAvailableForIme() const {
   return m_imeAcceptEvents ? focusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink