📰 Stop refreshing the whole NTP for every adapter change

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
index 2426ef7972aeec02e7ee04d14f418120ec759ac2..81017626c9535345ec6bc4a26d4865c1b36a7f5e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
@@ -18,7 +18,9 @@
 import android.support.annotation.Nullable;
 import android.support.v4.graphics.drawable.RoundedBitmapDrawable;
 import android.support.v4.graphics.drawable.RoundedBitmapDrawableFactory;
+import android.support.v7.widget.DefaultItemAnimator;
 import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.support.v7.widget.helper.ItemTouchHelper;
 import android.text.Editable;
 import android.text.TextUtils;
@@ -324,6 +326,17 @@ public void initialize(NewTabPageManager manager, boolean searchProviderHasLogo)
             // made for the ScrollView UI.
             ViewGroup.LayoutParams params = mNewTabPageLayout.getLayoutParams();
             params.height = ViewGroup.LayoutParams.WRAP_CONTENT;
+
+            mRecyclerView.setItemAnimator(new DefaultItemAnimator() {
+                @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();
+                }
+            });
         } else {
             stub.setLayoutResource(R.layout.new_tab_page_scroll_view);
             mScrollView = (NewTabPageScrollView) stub.inflate();
@@ -358,6 +371,7 @@ public void initialize(NewTabPageManager manager, boolean searchProviderHasLogo)
         if (mUseCardsUi) {
             mNewTabPageAdapter =
                     new NewTabPageAdapter(mManager, mNewTabPageLayout, mUiConfig);
+            mNewTabPageAdapter.initializeSections();
             mRecyclerView.setAdapter(mNewTabPageAdapter);
 
             // Set up swipe-to-dismiss