📰 [Reland] Spacing and fixes for the sign in promo

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageRecyclerView.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageRecyclerView.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageRecyclerView.java
index 1c28167249e8777696c95251c21f5e1a4592b3e0..ba14bf5028325fa77ca6952825abf3d8a6122fdf 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageRecyclerView.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageRecyclerView.java
@@ -29,6 +29,9 @@
 import org.chromium.chrome.browser.ntp.snippets.SnippetArticle;
 import org.chromium.chrome.browser.util.ViewUtils;
 
+import java.util.HashMap;
+import java.util.Map;
+
 /**
  * Simple wrapper on top of a RecyclerView that will acquire focus when tapped.  Ensures the
  * New Tab page receives focus when clicked.
@@ -49,6 +52,13 @@
      */
     private int mCompensationHeight;
 
+    /**
+     * Height compensation value for each item being dismissed. Since dismissals sometimes include
+     * sibling elements, and these don't get the standard treatment, we track the total height
+     * associated with the element the user interacted with.
+     */
+    private final Map<ViewHolder, Integer> mCompensationHeightMap = new HashMap<>();
+
     /** View used to calculate the position of the cards' snap point. */
     private View mAboveTheFoldView;
 
@@ -173,23 +183,23 @@ public void refreshBottomSpacing() {
      * below the fold to push the header up to to the top of the screen.
      */
     int calculateBottomSpacing() {
-        int firstHeaderPos = getNewTabPageAdapter().getFirstHeaderPosition();
+        int aboveTheFoldPosition = getNewTabPageAdapter().getAboveTheFoldPosition();
         int firstVisiblePos = mLayoutManager.findFirstVisibleItemPosition();
-        if (firstHeaderPos == RecyclerView.NO_POSITION
+        if (aboveTheFoldPosition == RecyclerView.NO_POSITION
                 || firstVisiblePos == RecyclerView.NO_POSITION) {
             return 0;
         }
 
-        // We have enough items to fill the view, since the snap point item is not even visible.
-        if (firstVisiblePos > firstHeaderPos) {
+        // We have enough items to fill the view, since the above-the-fold item is not even visible.
+        if (firstVisiblePos > aboveTheFoldPosition) {
             return 0;
         }
 
         ViewHolder lastContentItem = findLastContentItem();
-        ViewHolder firstHeader = findFirstHeader();
+        ViewHolder aboveTheFold = findViewHolderForAdapterPosition(aboveTheFoldPosition);
 
         int bottomSpacing = getHeight() - mToolbarHeight;
-        if (lastContentItem == null || firstHeader == null) {
+        if (lastContentItem == null || aboveTheFold == null) {
             // This can happen in several cases, where some elements are not visible and the
             // RecyclerView didn't already attach them. We handle it by just adding space to make
             // sure that we never run out and force the UI to jump around and get stuck in a
@@ -200,14 +210,14 @@ int calculateBottomSpacing() {
             //  - Dismissing a snippet and having the status card coming to take its place.
             //  - Refresh while being below the fold, for example by tapping the status card.
 
-            if (firstHeader != null) bottomSpacing -= firstHeader.itemView.getTop();
+            if (aboveTheFold != null) bottomSpacing -= aboveTheFold.itemView.getBottom();
 
             Log.w(TAG, "The RecyclerView items are not attached, can't determine the content "
                             + "height: snap=%s, last=%s. Using full height: %d ",
-                    firstHeader, lastContentItem, bottomSpacing);
+                    aboveTheFold, lastContentItem, bottomSpacing);
         } else {
             int contentHeight =
-                    lastContentItem.itemView.getBottom() - firstHeader.itemView.getTop();
+                    lastContentItem.itemView.getBottom() - aboveTheFold.itemView.getBottom();
             bottomSpacing -= contentHeight - mCompensationHeight;
         }
 
@@ -346,15 +356,28 @@ public NewTabPageLayout findAboveTheFoldView() {
     }
 
     /** Called when an item is in the process of being removed from the view. */
-    public void onItemDismissStarted(View itemView) {
-        mCompensationHeight += itemView.getHeight();
+    public void onItemDismissStarted(ViewHolder viewHolder) {
+        assert !mCompensationHeightMap.containsKey(viewHolder);
+
+        int dismissedHeight = viewHolder.itemView.getHeight();
+
+        ViewHolder siblingViewHolder = getNewTabPageAdapter().getDismissSibling(viewHolder);
+        if (siblingViewHolder != null) {
+            dismissedHeight += siblingViewHolder.itemView.getHeight();
+        }
+
+        mCompensationHeightMap.put(viewHolder, dismissedHeight);
+        mCompensationHeight += dismissedHeight;
         refreshBottomSpacing();
     }
 
     /** Called when an item has finished being removed from the view. */
-    public void onItemDismissFinished(View itemView) {
-        mCompensationHeight -= itemView.getHeight();
+    public void onItemDismissFinished(ViewHolder viewHolder) {
+        assert mCompensationHeightMap.containsKey(viewHolder);
+        mCompensationHeight -= mCompensationHeightMap.remove(viewHolder);
+
         assert mCompensationHeight >= 0;
+        refreshBottomSpacing();
     }
 
     /**
@@ -403,8 +426,13 @@ public void snapScroll(View fakeBox, int parentScrollY, int parentHeight) {
         if (peekingCardViewHolder != null && isFirstItemVisible()) {
             if (!mHasSpaceForPeekingCard) return;
 
+            ViewHolder firstHeaderViewHolder = findFirstHeader();
+            // It is possible to have a card but no header, for example the sign in promo.
+            // That one does not peek.
+            if (firstHeaderViewHolder == null) return;
+
             View peekingCardView = peekingCardViewHolder.itemView;
-            View headerView = findFirstHeader().itemView;
+            View headerView = firstHeaderViewHolder.itemView;
             final int peekingHeight = getResources().getDimensionPixelSize(
                     R.dimen.snippets_padding_and_peeking_card_height);
 
@@ -474,13 +502,13 @@ public void dismissItemWithAnimation(SnippetArticle suggestion) {
         animation.addListener(new AnimatorListenerAdapter() {
             @Override
             public void onAnimationStart(Animator animation) {
-                NewTabPageRecyclerView.this.onItemDismissStarted(itemView);
+                NewTabPageRecyclerView.this.onItemDismissStarted(viewHolder);
             }
 
             @Override
             public void onAnimationEnd(Animator animation) {
                 getNewTabPageAdapter().dismissItem(position);
-                NewTabPageRecyclerView.this.onItemDismissFinished(itemView);
+                NewTabPageRecyclerView.this.onItemDismissFinished(viewHolder);
             }
         });
         animation.start();