[NTP Snippets] Fill space below the last snippet if necessary

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java
index 57b908102cd1a135446c2ba46ee14481b70884d9..2e2c76d0d19c599f31e69835e2b10f547c370c0e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapter.java
@@ -41,7 +41,7 @@
     private final ItemTouchCallbacks mItemTouchCallbacks;
 
     private static final Interpolator FADE_INTERPOLATOR = new FastOutLinearInInterpolator();
-
+    private NewTabPageViewHolder mPaddingViewHolder;
     private class ItemTouchCallbacks extends ItemTouchHelper.Callback {
         @Override
         public void onSwiped(ViewHolder viewHolder, int direction) {
@@ -126,6 +126,7 @@ public void onSnippetsReceived(List<SnippetArticle> listSnippets) {
         // allocated even though visibility is set to GONE.
         // mNewTabPageListItems.add(new SnippetHeaderListItem());
         mNewTabPageListItems.addAll(listSnippets);
+        mNewTabPageListItems.add(new PaddingListItem());
 
         notifyDataSetChanged();
 
@@ -154,6 +155,11 @@ public NewTabPageViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                     SnippetArticleViewHolder.createView(parent), mNewTabPageManager);
         }
 
+        if (viewType == NewTabPageListItem.VIEW_TYPE_PADDING) {
+            mPaddingViewHolder = new NewTabPageViewHolder(PaddingListItem.createView(parent));
+            return mPaddingViewHolder;
+        }
+
         return null;
     }
 
@@ -173,14 +179,21 @@ private void dismissItem(int position) {
         mNewTabPageListItems.remove(position);
 
         int numRemovedItems = 1;
-        if (mNewTabPageListItems.size() == 2) {
-            // There's only the above-the-fold item and the header left, so we remove the header.
-            position = 1; // When present, the header is always at that position.
-            mNewTabPageListItems.remove(position);
-            ++numRemovedItems;
-        }
+        // TODO(https://crbug.com/608918): Remove this for now as we need to come up with a better

[May, 2016/05/10 10:31:51]

This doesn't seem to be the right bug number.

Also, Nicole ran into this problem with the headers. Apparently in a ListView
(also a RecyclerView), the view still takes up space even when GONE. The only
way to do this is to remove/add the item dynamically

[dgn, 2016/05/10 14:26:12]

It should have been commented out at the same time a line 127, so I just did it
and copied the explanation comment. 

Nicole, which bug did you intend to link there?

+        // way to visibly not affect the layout of the page when not shown as currently pixels are
+        // allocated even though visibility is set to GONE.
+//        if (mNewTabPageListItems.size() == 2) {
+//            // There's only the above-the-fold item and the header left, so we remove the header.
+//            position = 1; // When present, the header is always at that position.
+//            mNewTabPageListItems.remove(position);
+//            ++numRemovedItems;
+//        }
 
         notifyItemRangeRemoved(position, numRemovedItems);
+
+        if (mPaddingViewHolder != null && mPaddingViewHolder.itemView != null) {
+            mPaddingViewHolder.itemView.requestLayout();
+        }
     }
 
     List<NewTabPageListItem> getItemsForTesting() {