First step in enabling creating tabs without an Activity on Android.

content/public/browser/content_browser_client.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 "content/public/browser/content_browser_client.h"
 
 #include "base/files/file_path.h"
 #include "ui/gfx/image/image_skia.h"
 #include "url/gurl.h"
 
@@ skipping 324 matching lines @@
     MediaStreamType type) {
   return false;
 }
 
 PresentationServiceDelegate*
 ContentBrowserClient::GetPresentationServiceDelegate(
     WebContents* web_contents) {
   return nullptr;
 }
 
-WebContents* ContentBrowserClient::OpenURL(BrowserContext* browser_context,
-                                           const OpenURLParams& params) {
-  return nullptr;
+void ContentBrowserClient::OpenURL(
+    content::BrowserContext* browser_context,
+    const content::OpenURLParams& params,
+    const base::Callback<void(content::WebContents*)>& callback) {
+  callback.Run(nullptr);
 }
 
 #if defined(OS_WIN)
 const wchar_t* ContentBrowserClient::GetResourceDllName() {
   return nullptr;
 }
 #endif
 
 #if defined(VIDEO_HOLE)
 ExternalVideoSurfaceContainer*
 ContentBrowserClient::OverrideCreateExternalVideoSurfaceContainer(
     WebContents* web_contents) {
   return nullptr;
 }
 #endif
 
 }  // namespace content