[NTP OptOut] Fix cold start state for the expandable suggestion section

On cold start with a NTP opened as current tab and header is collapsed,
the suggestions status can be updated to explicitly disabled after the
UI is initialized, which removes the entire section including the
expandable header.

We should add the section back if necessary on status changed to
explicitly disabled.

Bug: 851516
Change-Id: Ied7c7737dfb22b3dc22f4a059c48f1b0793b681a
Reviewed-on: https://chromium-review.googlesource.com/1097226Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580684}

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

@@ -167,6 +167,12 @@ public class SectionList extends InnerNode<NewTabPageViewHolder, PartialBindCall
                 return;
 
             case CategoryStatus.CATEGORY_EXPLICITLY_DISABLED:
+                // Need to remove the entire section from the UI immediately. If the section is
+                // expandable, we may add the section back for displaying the header.
+                removeSection(mSections.get(category));
+                maybeAddSectionForHeader(category);
+                return;
+
             case CategoryStatus.LOADING_ERROR:
                 // Need to remove the entire section from the UI immediately.
                 removeSection(mSections.get(category));