Remove most native WebContents references from Java

chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellTabModel.java

 // Copyright 2014 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.
 
 package org.chromium.chrome.shell;
 
 import org.chromium.chrome.browser.Tab;
 import org.chromium.chrome.browser.tabmodel.TabModelBase;
 import org.chromium.chrome.browser.tabmodel.TabModelDelegate;
 import org.chromium.chrome.browser.tabmodel.TabModelOrderController;
+import org.chromium.content_public.browser.WebContents;
 
 /**
  * Basic implementation of TabModel for use in ChromeShell.
  */
 public class ChromeShellTabModel extends TabModelBase {
 
     public ChromeShellTabModel(TabModelOrderController orderController,
             TabModelDelegate modelDelegate) {
         super(false, orderController, modelDelegate);
     }
 
     @Override
-    protected Tab createTabWithNativeContents(boolean incognito, long nativeWebContents,
+    protected Tab createTabWithWebContents(boolean incognito, WebContents webContents,
             int parentId) {
         return null;
     }
 
     @Override
     protected Tab createNewTabForDevTools(String url) {
         assert false;
         return null;
     }
 
 }