Revert "Changed NavigationController access to through tab in Java code"

chrome/android/java/src/org/chromium/chrome/browser/download/ChromeDownloadDelegate.java

 // Copyright 2015 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.browser.download;
 
 import android.Manifest.permission;
 import android.app.Activity;
 import android.app.DownloadManager;
 import android.content.Context;
@@ skipping 11 matching lines @@
 import android.webkit.URLUtil;
 import android.widget.TextView;
 
 import org.chromium.base.Log;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.infobar.InfoBarIdentifier;
 import org.chromium.chrome.browser.infobar.SimpleConfirmInfoBarBuilder;
-import org.chromium.chrome.browser.navigation.NavigationHandler;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.base.WindowAndroid.PermissionCallback;
 import org.chromium.ui.widget.Toast;
 
 import java.io.File;
 
@@ skipping 534 matching lines @@
 
     /**
      * Close a blank tab just opened for the download purpose.
      * @return true iff the tab was (already) closed.
      */
     private boolean closeBlankTab() {
         if (mTab == null) {
             // We do not want caller to dismiss infobar.
             return true;
         }
-        NavigationHandler navigationHandler = mTab.getNavigationHandler();
-        boolean isInitialNavigation =
-                navigationHandler == null || navigationHandler.isInitialNavigation();
+        WebContents contents = mTab.getWebContents();
+        boolean isInitialNavigation = contents == null
+                || contents.getNavigationController().isInitialNavigation();
         if (isInitialNavigation) {
             // Tab is created just for download, close it.
             Activity activity = mTab.getWindowAndroid().getActivity().get();
             if (!(activity instanceof ChromeActivity)) return true;
 
             TabModelSelector selector = ((ChromeActivity) activity).getTabModelSelector();
             return selector == null ? true : selector.closeTab(mTab);
         }
         return false;
     }
@@ skipping 48 matching lines @@
     private static native String nativeGetDownloadWarningText(String filename);
     private static native boolean nativeIsDownloadDangerous(String filename);
     private static native void nativeDangerousDownloadValidated(
             Object tab, String downloadGuid, boolean accept);
     private static native void nativeLaunchDownloadOverwriteInfoBar(ChromeDownloadDelegate delegate,
             Tab tab, DownloadInfo downloadInfo, String fileName, String dirName,
             String dirFullPath);
     private static native void nativeLaunchPermissionUpdateInfoBar(
             Tab tab, String permission, long callbackId);
 }