[WebLayer] Add @VerifiedOnO annotation to autofill class

This class overrides onProvideAutofillVirtualStructure() which was added
in O.

Bug: 1085294
Change-Id: I29c8876f1340beef65350c2333f7f6ffd6d0540e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2222968
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Sam Maier <smaier@chromium.org>
Auto-Submit: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Sam Maier <smaier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773394}

weblayer/browser/java/org/chromium/weblayer_private/AutofillView.java

@@ -12,9 +12,12 @@ import android.view.ViewStructure;
 import android.view.autofill.AutofillValue;
 import android.widget.FrameLayout;
 
+import org.chromium.base.annotations.VerifiesOnO;
+
 /**
  * View which handles autofill support for a tab.
  */
+@VerifiesOnO
 public class AutofillView extends FrameLayout {
     private TabImpl mTab;