Ntp: restore scroll position.

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.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.ntp;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.content.res.Resources;
@@ skipping 278 matching lines @@
     /**
      * Initializes the NTP. This must be called immediately after inflation, before this object is
      * used in any other way.
      *
      * @param manager NewTabPageManager used to perform various actions when the user interacts
      *                with the page.
      * @param searchProviderHasLogo Whether the search provider has a logo.
      * @param snippetsBridge The optional bridge, that can be used to interact with the snippets.
      */
     public void initialize(NewTabPageManager manager, boolean searchProviderHasLogo,
-            SnippetsBridge snippetsBridge) {
+            SnippetsBridge snippetsBridge, int scrollPosition) {
         mManager = manager;
         mUiConfig = new UiConfig(this);
         ViewStub stub = (ViewStub) findViewById(R.id.new_tab_page_layout_stub);
 
         mUseCardsUi = snippetsBridge != null;
         if (mUseCardsUi) {
             stub.setLayoutResource(R.layout.new_tab_page_recycler_view);
             mRecyclerView = (NewTabPageRecyclerView) stub.inflate();
 
             // Don't attach now, the recyclerView itself will determine when to do it.
@@ skipping 35 matching lines @@
 
         mPendingLoadTasks++;
         mManager.setMostVisitedURLsObserver(
                 this, mMostVisitedDesign.getNumberOfTiles(searchProviderHasLogo));
 
         // Set up snippets
         if (mUseCardsUi) {
             mNewTabPageAdapter =
                     new NewTabPageAdapter(mManager, mNewTabPageLayout, snippetsBridge, mUiConfig);
             mRecyclerView.setAdapter(mNewTabPageAdapter);
+            mRecyclerView.scrollToPosition(scrollPosition);
 
             // Set up swipe-to-dismiss
             ItemTouchHelper helper =
                     new ItemTouchHelper(mNewTabPageAdapter.getItemTouchCallbacks());
             helper.attachToRecyclerView(mRecyclerView);
 
             mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                 private boolean mScrolledOnce = false;
                 @Override
                 public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
@@ skipping 806 matching lines @@
         mUiConfig.updateDisplayStyle();
     }
 
     private int getVerticalScroll() {
         if (mUseCardsUi) {
             return mRecyclerView.computeVerticalScrollOffset();
         } else {
             return mScrollView.getScrollY();
         }
     }
+
+    public int getScrollPosition() {

[Ted C, 2016/09/19 19:59:08]

javadoc (probably worth noting that it does not necessarily reflect the internal
scroll Y position but just a scroll value that allows this to return to a close
approximation of the previous state)

[Michael van Ouwerkerk, 2016/09/20 11:08:16]

Done.

+        return mRecyclerView.getScrollPosition();
+    }
 }