Fix devtools unable to start a shared workers.

chrome/browser/ui/webui/app_launcher_page_ui.cc

 // Copyright (c) 2013 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 "chrome/browser/ui/webui/app_launcher_page_ui.h"
 
 #include <string>
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 94 matching lines @@
 
 void AppLauncherPageUI::HTMLSource::StartDataRequest(
     const std::string& path,
     const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
     const content::URLDataSource::GotDataCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   NTPResourceCache* resource = AppResourceCacheFactory::GetForProfile(profile_);
   resource->set_should_show_other_devices_menu(false);
 
+  content::WebContents* web_contents = wc_getter.Run();
   content::RenderProcessHost* render_host =
-      wc_getter.Run()->GetRenderProcessHost();
+      web_contents ? web_contents->GetRenderProcessHost() : nullptr;
   NTPResourceCache::WindowType win_type = NTPResourceCache::GetWindowType(
       profile_, render_host);
   scoped_refptr<base::RefCountedMemory> html_bytes(
       resource->GetNewTabHTML(win_type));
 
   callback.Run(html_bytes.get());
 }
 
 std::string AppLauncherPageUI::HTMLSource::GetMimeType(
     const std::string& resource) const {
@@ skipping 15 matching lines @@
   return "style-src 'self' chrome://resources chrome://theme 'unsafe-inline';";
 }
 
 std::string AppLauncherPageUI::HTMLSource::GetContentSecurityPolicyImgSrc()
     const {
   return "img-src chrome://extension-icon chrome://theme chrome://resources "
       "data:;";
 }
 
 AppLauncherPageUI::HTMLSource::~HTMLSource() {}