Fix NullPointerException at LensChipDelegate#onMenuClosed

Change-Id: I4c5fdbd3648e088353db5491084c3247b0f40968
Bug: 1155490
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2574478Reviewed-by: Ben Goldberger <benwgold@google.com>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Sinan Sahin <sinansahin@google.com>
Commit-Queue: Yu Su <yusuyoutube@google.com>
Cr-Commit-Position: refs/heads/master@{#833760}

chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java

@@ -184,7 +184,7 @@ public class ContextMenuHelper {
                 mCurrentPopulator.onMenuClosed();
                 mCurrentPopulator = null;
             }
-            if (LensUtils.enableImageChip(mIsIncognito)) {
+            if (mChipDelegate != null) {
                 // If the image was being classified terminate the classification
                 // Has no effect if the classification already succeeded.
                 mChipDelegate.onMenuClosed();