Tentative fix for scroll event related crashes on the NTP

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 1e30b4fe978801bbf432baf2421ec5e89b8cc2bd..87b9654b15ce4d3559fc403dfea16a95ad58ec4c 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
@@ -300,6 +300,12 @@ public class NewTabPageView extends FrameLayout
          * Page goes away.
          */
         void registerSignInStateObserver(SignInStateObserver signInStateObserver);
+
+        /**
+         * @return whether the {@link NewTabPage} associated with this manager is the current page
+         * displayed to the user.
+         */
+        boolean isCurrentPage();
     }
 
     /**
@@ -491,6 +497,12 @@ public class NewTabPageView extends FrameLayout
     private void updateSearchBoxOnScroll() {
         if (mDisableUrlFocusChangeAnimations) return;
 
+        // When the page changes (tab switching or new page loading), it is possible that events
+        // (e.g. delayed RecyclerView change notifications) trigger calls to these methods after
+        // the current page changes. We check it again to make sure we don't attempt to update the
+        // wrong page.
+        if (!mManager.isCurrentPage()) return;
+
         if (mSearchBoxScrollListener != null) {
             mSearchBoxScrollListener.onNtpScrollChanged(getToolbarTransitionPercentage());
         }