📰 Fix crash when tapping the menu on closed NTP

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/ContextMenuManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/ContextMenuManager.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/ContextMenuManager.java
index 79910e5857edb491729a8f3a898764bae5f45968..fda2dde2e44a70f861edf9433745d4a84ba75af1 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/ContextMenuManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/ContextMenuManager.java
@@ -7,6 +7,7 @@
 import android.app.Activity;
 import android.support.annotation.IntDef;
 import android.support.annotation.StringRes;
+import android.support.v13.view.ViewCompat;
 import android.view.ContextMenu;
 import android.view.Menu;
 import android.view.MenuItem;
@@ -80,7 +81,7 @@ public ContextMenuManager(
      *                 are tapped.
      */
     public void createContextMenu(ContextMenu menu, View associatedView, Delegate delegate) {
-        OnMenuItemClickListener listener = new ItemClickListener(delegate);
+        OnMenuItemClickListener listener = new ItemClickListener(delegate, associatedView);
         boolean hasItems = false;
 
         for (@ContextMenuItemId int itemId : MenuItemLabelMatcher.STRING_MAP.keySet()) {
@@ -167,13 +168,23 @@ private boolean shouldShowItem(@ContextMenuItemId int itemId, Delegate delegate)
 
     private static class ItemClickListener implements OnMenuItemClickListener {
         private final Delegate mDelegate;
+        private final View mAssociatedView;
 
-        ItemClickListener(Delegate delegate) {
+        ItemClickListener(Delegate delegate, View associatedView) {
             mDelegate = delegate;
+            mAssociatedView = associatedView;
         }
 
         @Override
         public boolean onMenuItemClick(MenuItem item) {
+            // If the user clicks a snippet then immediately long presses they will create a context
+            // menu while the snippet's URL loads in the background. This means that when they press
+            // an item on context menu the NTP will not actually be open. We add this check here to
+            // prevent taking any action if the user has left the NTP. (https://crbug.com/640468)
+            // Although the menu is supposed to be closed when we navigate away from the NTP, we
+            // have to keep this check because of race conditions. (https://crbug.com/668945)
+            if (!ViewCompat.isAttachedToWindow(mAssociatedView)) return true;
+
             switch (item.getItemId()) {
                 case ID_OPEN_IN_NEW_WINDOW:
                     mDelegate.openItem(WindowOpenDisposition.NEW_WINDOW);