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

third_party/WebKit/Source/web/tests/WebViewTest.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 2082 matching lines @@
   webView->handleInputEvent(WebCoalescedInputEvent(event));
   runPendingTasks();
   EXPECT_EQ(25, client.longpressX());
   EXPECT_EQ(7, client.longpressY());
 
   // Explicitly reset to break dependency on locally scoped client.
   m_webViewHelper.reset();
 }
 
 TEST_P(WebViewTest, ClientTapHandlingNullWebViewClient) {
-  WebViewImpl* webView =
-      WebViewImpl::create(nullptr, WebPageVisibilityStateVisible);
+  WebViewImpl* webView = WebViewImpl::create(WebPageVisibilityStateVisible);
   FrameTestHelpers::TestWebFrameClient webFrameClient;
   FrameTestHelpers::TestWebWidgetClient webWidgetClient;
   WebLocalFrame* localFrame = WebLocalFrame::create(
       WebTreeScopeType::Document, &webFrameClient, nullptr, nullptr);
   webView->setMainFrame(localFrame);
 
   // TODO(dcheng): The main frame widget currently has a special case.
   // Eliminate this once WebView is no longer a WebWidget.
   blink::WebFrameWidget::create(&webWidgetClient, webView, localFrame);
 
@@ skipping 2218 matching lines @@
   EXPECT_FALSE(frameView->visualViewportSuppliesScrollbars());
   if (RuntimeEnabledFeatures::rootLayerScrollingEnabled()) {
     EXPECT_NE(nullptr,
               frameView->layoutViewportScrollableArea()->verticalScrollbar());
   } else {
     EXPECT_NE(nullptr, frameView->verticalScrollbar());
   }
 }
 
 }  // namespace blink