[TTS] Add a Feature and about:flag for Single Actions.

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchFieldTrial.java

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchFieldTrial.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchFieldTrial.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchFieldTrial.java
index cc237ce86acdfd30c90b87b0c5627c5c39d629ce..23c0928a6ea785c56ec7d56566cf452637d396fc 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchFieldTrial.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchFieldTrial.java
@@ -9,6 +9,7 @@ import android.text.TextUtils;
 import org.chromium.base.CommandLine;
 import org.chromium.base.SysUtils;
 import org.chromium.base.VisibleForTesting;
+import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.components.variations.VariationsAssociatedData;
 
@@ -104,6 +105,7 @@ public class ContextualSearchFieldTrial {
     private static Boolean sIsContextualCardsBarIntegrationEnabled;
     private static Boolean sIsOnlineDetectionDisabled;
     private static Boolean sIsAmpAsSeparateTabEnabled;
+    private static Boolean sContextualSearchSingleActionsEnabled;
 
     /**
      * Don't instantiate.
@@ -405,6 +407,22 @@ public class ContextualSearchFieldTrial {
         return sIsOnlineDetectionDisabled;
     }
 
+    // ---------------
+    // Features.
+    // ---------------
+
+    /**
+     * @return Whether or not single actions based on Contextual Cards is enabled.
+     */
+    static boolean isContextualSearchSingleActionsEnabled() {
+        if (sContextualSearchSingleActionsEnabled == null) {
+            sContextualSearchSingleActionsEnabled =
+                    ChromeFeatureList.isEnabled(ChromeFeatureList.CONTEXTUAL_SEARCH_SINGLE_ACTIONS);
+        }
+
+        return sContextualSearchSingleActionsEnabled;
+    }
+
     // --------------------------------------------------------------------------------------------
     // Helpers.
     // --------------------------------------------------------------------------------------------