[Feed] Fix toolbar is gone on toggled article section header

Update search box on content changed because OnScrolled might not be
called or the vertical offset might be be reliable.

Bug: 887628
Change-Id: I429b817abd44f1a8e66b616dfad5f190f6fd8822
Reviewed-on: https://chromium-review.googlesource.com/1238619
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593387}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/FeedNewTabPageMediator.java

@@ -127,7 +127,10 @@ class FeedNewTabPageMediator
         };
         stream.addScrollListener(mStreamScrollListener);
 
-        mStreamContentChangedListener = () -> mStreamContentChanged = true;
+        mStreamContentChangedListener = () -> {
+            mStreamContentChanged = true;
+            mSnapScrollHelper.resetSearchBoxOnScroll(true);
+        };
         stream.addOnContentChangedListener(mStreamContentChangedListener);
 
         boolean suggestionsVisible =

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

@@ -39,8 +39,6 @@ import org.chromium.chrome.browser.widget.displaystyle.UiConfig;
 public class NewTabPageView extends FrameLayout {
     private static final String TAG = "NewTabPageView";
 
-    private final int mScrollToSuggestionsOffset;
-
     private NewTabPageRecyclerView mRecyclerView;
 
     private NewTabPageLayout mNewTabPageLayout;
@@ -49,7 +47,6 @@ public class NewTabPageView extends FrameLayout {
     private Tab mTab;
     private SnapScrollHelper mSnapScrollHelper;
     private UiConfig mUiConfig;
-    private Runnable mUpdateSearchBoxOnScrollRunnable;
 
     private boolean mNewTabPageRecyclerViewChanged;
     private int mSnapshotWidth;
@@ -93,9 +90,6 @@ public class NewTabPageView extends FrameLayout {
     public NewTabPageView(Context context, AttributeSet attrs) {
         super(context, attrs);
 
-        mScrollToSuggestionsOffset =
-                getResources().getDimensionPixelSize(R.dimen.toolbar_height_no_shadow);
-
         mRecyclerView = new NewTabPageRecyclerView(getContext());
 
         // Don't attach now, the recyclerView itself will determine when to do it.
@@ -150,7 +144,7 @@ public class NewTabPageView extends FrameLayout {
 
                 // Cancel any pending scroll update handling, a new one will be scheduled in
                 // onAnimationFinished().
-                mRecyclerView.removeCallbacks(mUpdateSearchBoxOnScrollRunnable);
+                mSnapScrollHelper.resetSearchBoxOnScroll(false);
 
                 return super.animateMove(holder, fromX, fromY, toX, toY);
             }
@@ -169,8 +163,7 @@ public class NewTabPageView extends FrameLayout {
                 if (viewHolder.itemView == mNewTabPageLayout) {
                     mNewTabPageLayout.setIsViewMoving(false);
                 }
-                mRecyclerView.removeCallbacks(mUpdateSearchBoxOnScrollRunnable);
-                mRecyclerView.post(mUpdateSearchBoxOnScrollRunnable);
+                mSnapScrollHelper.resetSearchBoxOnScroll(true);
             }
         });
 
@@ -178,8 +171,6 @@ public class NewTabPageView extends FrameLayout {
         OfflinePageBridge offlinePageBridge =
                 SuggestionsDependencyFactory.getInstance().getOfflinePageBridge(profile);
 
-        mUpdateSearchBoxOnScrollRunnable = mNewTabPageLayout::updateSearchBoxOnScroll;
-
         initializeLayoutChangeListener();
         mNewTabPageLayout.setSearchProviderInfo(searchProviderHasLogo, searchProviderIsGoogle);
 

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

@@ -23,6 +23,7 @@ public class SnapScrollHelper {
     private final NewTabPageManager mManager;
     private final NewTabPageLayout mNewTabPageLayout;
     private final Runnable mSnapScrollRunnable;
+    private final Runnable mUpdateSearchBoxOnScrollRunnable;
     private final int mToolbarHeight;
     private final int mSearchBoxTransitionLength;
 
@@ -40,6 +41,7 @@ public class SnapScrollHelper {
         mManager = manager;
         mNewTabPageLayout = newTabPageLayout;
         mSnapScrollRunnable = new SnapScrollRunnable();
+        mUpdateSearchBoxOnScrollRunnable = mNewTabPageLayout::updateSearchBoxOnScroll;
 
         Resources res = newTabPageLayout.getResources();
         mToolbarHeight = res.getDimensionPixelSize(R.dimen.toolbar_height_no_shadow)
@@ -88,6 +90,18 @@ public class SnapScrollHelper {
         mNewTabPageLayout.updateSearchBoxOnScroll();
     }
 
+    /**
+     * Resets any pending callbacks to update the search box position, and add new callback to
+     * update the search box position if necessary. This is used whenever {@link #handleScroll()} is
+     * not reliable (e.g. when an item is dismissed, the items at the top of the viewport might not
+     * move, and onScrolled() might not be called).
+     * @param update Whether a new callback to update search box should be posted to {@link #mView}.
+     */
+    public void resetSearchBoxOnScroll(boolean update) {
+        mView.removeCallbacks(mUpdateSearchBoxOnScrollRunnable);
+        if (update) mView.post(mUpdateSearchBoxOnScrollRunnable);
+    }
+
     /**
      * @param scrollPosition The scroll position that the snap scroll calculation is based on.
      * @return The modified scroll position that accounts for snap scroll.