NTP: Prevent conflict of dismiss animations and scroll position handling.

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.graphics.Canvas;
@@ skipping 83 matching lines @@
 
     private OnSearchBoxScrollListener mSearchBoxScrollListener;
 
     private ChromeActivity mActivity;
     private NewTabPageManager mManager;
     private LogoView.Delegate mLogoDelegate;
     private TileGroup.Delegate mTileGroupDelegate;
     private TileGroup mTileGroup;
     private UiConfig mUiConfig;
     private Runnable mSnapScrollRunnable;
+    private Runnable mUpdateSearchBoxOnScrollRunnable;
     private boolean mFirstShow = true;
     private boolean mSearchProviderHasLogo = true;
     private boolean mPendingSnapScroll;
     private boolean mInitialized;
     private int mLastScrollY = -1;
 
     /**
      * The number of asynchronous tasks that need to complete before the page is done loading.
      * This starts at one to track when the view is finished attaching to the window.
      */
@@ skipping 75 matching lines @@
 
         mRecyclerView = new NewTabPageRecyclerView(getContext());
         mRecyclerView.setContainsLocationBar(manager.isLocationBarShownInNTP());
         addView(mRecyclerView);
 
         // Don't attach now, the recyclerView itself will determine when to do it.
         mNewTabPageLayout = mRecyclerView.getAboveTheFoldView();
 
         mRecyclerView.setItemAnimator(new DefaultItemAnimator() {
             @Override
+            public boolean animateMove(ViewHolder holder, int fromX, int fromY, int toX, int toY) {
+                // If |mNewTabPageLayout| is animated by the RecyclerView because an item below it
+                // was dismissed, avoid also manipulating its vertical offset in our scroll handling
+                // at the same time. The onScrolled() method is called when an item is dismissed and
+                // the item at the top of the viewport is repositioned.
+                if (holder.itemView == mNewTabPageLayout) setUrlFocusAnimationsDisabled(true);
+
+                // Cancel any pending scroll update handling, a new one will be scheduled in
+                // onAnimationFinished().
+                mRecyclerView.removeCallbacks(mUpdateSearchBoxOnScrollRunnable);
+
+                return super.animateMove(holder, fromX, fromY, toX, toY);
+            }
+
+            @Override
             public void onAnimationFinished(ViewHolder viewHolder) {
                 super.onAnimationFinished(viewHolder);
-                // When removing sections, because the animations are all translations, the
-                // scroll events don't fire and we can get in the situation where the toolbar
-                // buttons disappear.
-                updateSearchBoxOnScroll();
+
+                // When an item is dismissed, the items at the top of the viewport might not move,
+                // and onScrolled() might not be called. We can get in the situation where the
+                // toolbar buttons disappear, so schedule an update for it. This can be cancelled
+                // from animateMove() in case |mNewTabPageLayout| will be moved. We don't know that
+                // from here, as the RecyclerView will animate multiple items when one is dismissed,
+                // and some will "finish" synchronously if they are already in the correct place,
+                // before other moves have even been scheduled.
+                if (viewHolder.itemView == mNewTabPageLayout) setUrlFocusAnimationsDisabled(false);
+                mRecyclerView.removeCallbacks(mUpdateSearchBoxOnScrollRunnable);
+                mRecyclerView.post(mUpdateSearchBoxOnScrollRunnable);
             }
         });
 
         mContextMenuManager =
                 new ContextMenuManager(mActivity, mManager.getNavigationDelegate(), mRecyclerView);
         mActivity.getWindowAndroid().addContextMenuCloseListener(mContextMenuManager);
         manager.addDestructionObserver(new DestructionObserver() {
             @Override
             public void onDestroy() {
                 mActivity.getWindowAndroid().removeContextMenuCloseListener(mContextMenuManager);
             }
         });
 
         OfflinePageBridge offlinePageBridge =
                 OfflinePageBridge.getForProfile(Profile.getLastUsedProfile());
 
         mTileGridLayout = (TileGridLayout) mNewTabPageLayout.findViewById(R.id.tile_grid_layout);
         mTileGridLayout.setMaxRows(getMaxTileRows(searchProviderHasLogo));
         mTileGridLayout.setMaxColumns(getMaxTileColumns());
         mTileGroup = new TileGroup(mActivity, mManager, mContextMenuManager, mTileGroupDelegate,
                 /* observer = */ this, offlinePageBridge, getTileTitleLines());
 
         mSearchProviderLogoView =
                 (LogoView) mNewTabPageLayout.findViewById(R.id.search_provider_logo);
         mLogoDelegate = new LogoDelegateImpl(tab, mSearchProviderLogoView);
         mSearchBoxView = mNewTabPageLayout.findViewById(R.id.search_box);
         mNoSearchLogoSpacer = mNewTabPageLayout.findViewById(R.id.no_search_logo_spacer);
 
         mSnapScrollRunnable = new SnapScrollRunnable();
+        mUpdateSearchBoxOnScrollRunnable = new UpdateSearchBoxOnScrollRunnable();
 
         initializeSearchBoxTextView();
         initializeVoiceSearchButton();
         initializeLayoutChangeListeners();
         setSearchProviderHasLogo(searchProviderHasLogo);
 
         tab.addObserver(new EmptyTabObserver() {
             @Override
             public void onShown(Tab tab) {
                 mTileGroup.onSwitchToForeground();
@@ skipping 684 matching lines @@
 
     private class SnapScrollRunnable implements Runnable {
         @Override
         public void run() {
             assert mPendingSnapScroll;
             mPendingSnapScroll = false;
 
             mRecyclerView.snapScroll(mSearchBoxView, getHeight());
         }
     }
+
+    private class UpdateSearchBoxOnScrollRunnable implements Runnable {
+        @Override
+        public void run() {
+            updateSearchBoxOnScroll();
+        }
+    }
 }