Make the WebWidgetClient parameter a ref so it's not legal to pass a nullptr.

components/printing/renderer/print_web_view_helper.cc

 // Copyright (c) 2012 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.
 
 #include "components/printing/renderer/print_web_view_helper.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 571 matching lines @@
                                page_layout.content_height);
 
   blink::WebView* web_view =
       blink::WebView::create(nullptr, blink::WebPageVisibilityStateVisible);
   web_view->settings()->setJavaScriptEnabled(true);
 
   blink::WebFrameClient frame_client;
   blink::WebLocalFrame* frame = blink::WebLocalFrame::create(
       blink::WebTreeScopeType::Document, &frame_client, nullptr, nullptr);
   web_view->setMainFrame(frame);
-  blink::WebFrameWidget::create(nullptr, web_view, frame);
+  blink::WebWidgetClient web_widget_client;
+  blink::WebFrameWidget::create(&web_widget_client, web_view, frame);
 
   base::Value html(ResourceBundle::GetSharedInstance().GetLocalizedString(
       IDR_PRINT_PREVIEW_PAGE));
   // Load page with script to avoid async operations.
   ExecuteScript(frame, kPageLoadScriptFormat, html);
 
   std::unique_ptr<base::DictionaryValue> options(new base::DictionaryValue());
   options.reset(new base::DictionaryValue());
   options->SetDouble(kSettingHeaderFooterDate, base::Time::Now().ToJsTime());
   options->SetDouble("width", page_size.width);
@@ skipping 1765 matching lines @@
       blink::WebConsoleMessage::LevelWarning, message));
   return false;
 }
 
 void PrintWebViewHelper::ScriptingThrottler::Reset() {
   // Reset counter on successful print.
   count_ = 0;
 }
 
 }  // namespace printing