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

chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.java
index 662f8db02b84f934db2e9949c91543de0668ba1f..2b872939ce95f75ccba0aa6dcf886ec34491d493 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.java
@@ -48,10 +48,12 @@ public abstract class ChromeFeatureList {
         return sTestEnabledFeatures.contains(featureName);
     }
 
+    // Alphabetical:
     public static final String ANDROID_PAY_INTEGRATION_V1 = "AndroidPayIntegrationV1";
     public static final String AUTOFILL_SCAN_CARDHOLDER_NAME = "AutofillScanCardholderName";
     public static final String CCT_EXTERNAL_LINK_HANDLING = "CCTExternalLinkHandling";
     public static final String CHROME_HOME = "ChromeHome";
+    public static final String CONTEXTUAL_SEARCH_SINGLE_ACTIONS = "ContextualSearchSingleActions";
     /** Whether we show an important sites dialog in the "Clear Browsing Data" flow. */
     public static final String IMPORTANT_SITES_IN_CBD = "ImportantSitesInCBD";
     public static final String NO_CREDIT_CARD_ABORT = "NoCreditCardAbort";