Remove deprecated FieldTrialHelper.

The downstream dependencies in Chrome for Android have been
updated to use org.chromium.base.FieldTrialList, so the old
code can be removed.

BUG=378035

Review URL: https://codereview.chromium.org/378403002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282251 0039d316-1c4b-4281-b951-d872f2087c98

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

-// Copyright 2013 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;
-
-import org.chromium.base.FieldTrialList;
-
-/**
- * Helper to get field trial information.
- */
-public class FieldTrialHelper {
-
-    private FieldTrialHelper() {}
-
-    /**
-     * This function has been moved to base so it can be used by //sync.
-     * Please use {@link FieldTrialList#findFullName()} instead.
-     * See http://crbug.com/378035 for context.
-     *
-     * @param trialName The name of the trial to get the group for.
-     * @return The group name chosen for the named trial, or the empty string if the trial does
-     *         not exist.
-     */
-    @Deprecated
-    public static String getFieldTrialFullName(String trialName) {
-        return FieldTrialList.findFullName(trialName);
-    }
-}