Refactor and extend SnippetsBridge for multi-section support

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 0781498e04e232bdd5fbf4e71eb900c5c9a18f79..b158127fa726cb1c417e1c7c96386fa2f1974d05 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
@@ -146,10 +146,15 @@ public class NewTabPageRecyclerView extends RecyclerView {
      * below the fold to push the header up to to the top of the screen.
      */
     int calculateBottomSpacing() {
+        int firstHeaderPos = getNewTabPageAdapter().getFirstHeaderPosition();
         int firstVisiblePos = mLayoutManager.findFirstVisibleItemPosition();
+        if (firstHeaderPos == RecyclerView.NO_POSITION
+                || firstVisiblePos == RecyclerView.NO_POSITION) {
+            return mMinBottomSpacing;
+        }
 
         // We have enough items to fill the view, since the snap point item is not even visible.
-        if (firstVisiblePos > getNewTabPageAdapter().getFirstHeaderPosition()) {
+        if (firstVisiblePos > firstHeaderPos) {
             return mMinBottomSpacing;
         }