Add an experimental standalone content suggestions UI.

chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuPropertiesDelegate.java

Index: chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuPropertiesDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuPropertiesDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuPropertiesDelegate.java
index 6d0529a89bc7aecefc991494bf7f4ee2538ba244..26a33426b3c23825f43d5be3f7aa2a18e4f31676 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuPropertiesDelegate.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuPropertiesDelegate.java
@@ -13,6 +13,7 @@ import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.CommandLine;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.ShortcutHelper;
 import org.chromium.chrome.browser.UrlConstants;
@@ -192,6 +193,11 @@ public class AppMenuPropertiesDelegate {
             // Only display the Enter VR button if VR Shell Dev environment is enabled.
             menu.findItem(R.id.enter_vr_id).setVisible(
                     CommandLine.getInstance().hasSwitch(ChromeSwitches.ENABLE_VR_SHELL_DEV));
+
+            // Only display the standalone content suggestions UI if the corresponding feature
+            // is enabled.
+            menu.findItem(R.id.content_suggestions_standalone_ui).setVisible(
+                    ChromeFeatureList.isEnabled(ChromeFeatureList.NTP_SUGGESTIONS_STANDALONE_UI));
         }
 
         if (isOverviewMenu) {