Refine snap scrolling on the Cards New Tab Page.

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardsLayoutOperations.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardsLayoutOperations.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardsLayoutOperations.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardsLayoutOperations.java
deleted file mode 100644
index ab4717312a9750255946d393884423e9da1f51d9..0000000000000000000000000000000000000000
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardsLayoutOperations.java
+++ /dev/null
@@ -1,76 +0,0 @@
-// Copyright 2016 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.cards;
-
-import org.chromium.chrome.browser.ntp.MostVisitedLayout;
-import org.chromium.chrome.browser.ntp.NewTabPageLayout;
-import org.chromium.chrome.browser.ntp.NewTabPageUma;
-import org.chromium.chrome.browser.ntp.NewTabPageUma.SnapState;
-
-
-/**
- * This is a class to organise the various layout operations of the New Tab Page while using the
- * cards layout. For example, updating the size of the peeking card or controlling the scroll
- * behaviour.
- */
-public class CardsLayoutOperations {
-
-    /**
-     * Snaps the scroll point to the top of the screen, the top of most visited or to articles
-     * depending on the current scroll. This function makes gross assumptions about the layout, so
-     * will probably need to be changed if the new tab page changes.
-     * @param recyclerView The NewTabPageRecyclerView containing everything.
-     * @param newTabPageLayout The above the fold content.
-     * @param mostVisitedLayout The view to snap to while snapping to most visited.
-     * @param currentScroll The current scroll.
-     * @param forceMostLikelySnap Whether to force snapping to most likely.
-     * @return Whether the snap point was above or below the fold.
-     */
-    public static NewTabPageUma.SnapState snapScroll(NewTabPageRecyclerView recyclerView,
-            NewTabPageLayout newTabPageLayout, MostVisitedLayout mostVisitedLayout,
-            int currentScroll, boolean forceMostLikelySnap) {
-        // These calculations only work if the first item is visible (since
-        // computeVerticalScrollOffset only takes into account visible items).
-        // Luckily, we only need to perform the calculations if the first item is visible.
-        if (!recyclerView.isFirstItemVisible()) {
-            return SnapState.BELOW_THE_FOLD;
-        }
-
-        // If snapping to Most Likely or to Articles, the omnibox will be at the top of the
-        // page, so offset the scroll so the scroll targets appear below it.
-        final int omniBoxHeight = newTabPageLayout.getPaddingTop();
-        final int topOfMostLikelyScroll = mostVisitedLayout.getTop() - omniBoxHeight;
-        final int topOfSnippetsScroll = newTabPageLayout.getHeight() - omniBoxHeight;
-
-        assert currentScroll >= 0;
-        // Do not do any scrolling if the user is currently viewing articles.
-        if (currentScroll >= topOfSnippetsScroll) {
-            return SnapState.BELOW_THE_FOLD;
-        }
-
-        // If Most Likely is fully visible when we are scrolled to the top, we have two
-        // snap points: the Top and Articles.
-        // If not, we have three snap points: the Top, Most Likely and Articles.
-        boolean snapToMostLikely =
-                 forceMostLikelySnap || recyclerView.getHeight() < mostVisitedLayout.getBottom();
-
-        int targetScroll;
-        if (currentScroll < newTabPageLayout.getHeight() / 3) {
-            // In either case, if in the top 1/3 of the original NTP, snap to the top.
-            targetScroll = 0;
-        } else if (snapToMostLikely
-                && currentScroll < newTabPageLayout.getHeight() * 2 / 3) {
-            // If in the middle 1/3 and we are snapping to Most Likely, snap to it.
-            targetScroll = topOfMostLikelyScroll;
-        } else {
-            // Otherwise, snap to the Articles.
-            targetScroll = topOfSnippetsScroll;
-        }
-        recyclerView.smoothScrollBy(0, targetScroll - currentScroll);
-
-        return targetScroll == topOfSnippetsScroll
-                ? SnapState.BELOW_THE_FOLD : SnapState.ABOVE_THE_FOLD;
-    }
-}