Add chrome://flags for update menu item

chrome/android/java/src/org/chromium/chrome/browser/omaha/UpdateMenuItemHelper.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.omaha;
 
 import android.content.ActivityNotFoundException;
 import android.content.Context;
 import android.content.Intent;
 import android.graphics.Bitmap;
@@ skipping 140 matching lines @@
         }
 
         return updateAvailable(activity);
     }
 
     /**
      * @param context The current {@link Context}.
      * @return The string to use for summary text or the empty string if no summary should be shown.
      */
     public String getMenuItemSummaryText(Context context) {
-        if (!getBooleanParam(SHOW_SUMMARY)) {
+        if (!getBooleanParam(SHOW_SUMMARY) && !getBooleanParam(CUSTOM_SUMMARY)) {
             return "";
         }
 
         String customSummary = getStringParamValue(CUSTOM_SUMMARY);
         if (!TextUtils.isEmpty(customSummary)) {
             return customSummary;
         }
 
         return context.getResources().getString(R.string.menu_update_summary_default);
     }
@@ skipping 138 matching lines @@
      * @return The command-line flag value if present, or the param is value if present.
      */
     private static String getStringParamValue(String paramName) {
         String value = CommandLine.getInstance().getSwitchValue(paramName);
         if (TextUtils.isEmpty(value)) {
             value = VariationsAssociatedData.getVariationParamValue(FIELD_TRIAL_NAME, paramName);
         }
         return value;
     }
 }