[Herb] Set up field trial for UI prototypes

chrome/android/java/src/org/chromium/chrome/browser/preferences/ChromePreferenceManager.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.preferences;
 
 import android.content.Context;
 import android.content.SharedPreferences;
-import android.os.StrictMode;
 import android.preference.PreferenceManager;
-import android.text.TextUtils;
 
-import org.chromium.base.ApplicationStatus;
-import org.chromium.base.CommandLine;
-import org.chromium.base.Log;
 import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.chrome.browser.ChromeSwitches;
-import org.chromium.chrome.browser.ChromeVersionInfo;
 import org.chromium.chrome.browser.crash.MinidumpUploadService.ProcessType;
 import org.chromium.chrome.browser.signin.SigninPromoUma;
-import org.chromium.ui.base.DeviceFormFactor;
+import org.chromium.chrome.browser.util.FeatureUtilities;
 
 import java.util.Locale;
 
 
 /**
  * ChromePreferenceManager stores and retrieves various values in Android shared preferences.
  */
 public class ChromePreferenceManager {
     /**
      * Preference that denotes that Chrome has attempted to migrate from tabbed mode to document
@@ skipping 20 matching lines @@
     private static final String ENABLE_CUSTOM_TABS = "enable_custom_tabs";
     private static final String HERB_FLAVOR_KEY = "herb_flavor";
 
     private static final String SUCCESS_UPLOAD_SUFFIX = "_crash_success_upload";
     private static final String FAILURE_UPLOAD_SUFFIX = "_crash_failure_upload";
 
     private static final int SIGNIN_PROMO_CYCLE_IN_DAYS = 120;
     private static final long MILLISECONDS_IN_DAY = 1000 * 60 * 60 * 24;
 
     private static ChromePreferenceManager sPrefs;
-    private static String sCachedHerbFlavor;
-    private static boolean sIsHerbFlavorCached;
 
     private final SharedPreferences mSharedPreferences;
     private final Context mContext;
 
     private ChromePreferenceManager(Context context) {
         mContext = context.getApplicationContext();
         mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
     }
 
     /**
@@ skipping 252 matching lines @@
 
     /**
      * Sets the number of tap gestures that have been received when not waiting for the promo.
      * @param count Number of taps that have been received when not waiting for the promo.
      */
     public void setContextualSearchTapCount(int count) {
         writeInt(CONTEXTUAL_SEARCH_TAP_COUNT, count);
     }
 
     /**
-     * @return Which flavor of Herb is active, or null if a prototype isn't being tested.
+     * @return Which UI prototype the user is testing. This is cached from native via
+     *         {@link FeatureUtilities#cacheHerbFlavor}.
      */
-    public static String getHerbFlavor() {
-        if (!sIsHerbFlavorCached) {
-            Context context = ApplicationStatus.getApplicationContext();
-            if (ChromeVersionInfo.isStableBuild() || ChromeVersionInfo.isBetaBuild()) return null;
-            if (DeviceFormFactor.isTablet(context)) return null;
-
-            // Allowing disk access for preferences while prototyping.
-            sCachedHerbFlavor = null;
-            StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
-            try {
-                sCachedHerbFlavor =
-                        ChromePreferenceManager.getInstance(context).getHerbFlavorInternal();
-            } finally {
-                StrictMode.setThreadPolicy(oldPolicy);
-            }
-
-            sIsHerbFlavorCached = true;
-            Log.d(TAG, "Retrieved Herb flavor: " + sCachedHerbFlavor);
-        }
-
-        return sCachedHerbFlavor;
-    }
-
-    private String getHerbFlavorInternal() {
-        return mSharedPreferences.getString(HERB_FLAVOR_KEY, null);
+    public String getCachedHerbFlavor() {
+        return mSharedPreferences.getString(HERB_FLAVOR_KEY, ChromeSwitches.HERB_FLAVOR_DISABLED);
     }
 
     /**
-     * Caches which flavor of Herb the user prefers from native.
+     * Caches which UI prototype the user is testing.
      */
-    public static boolean cacheHerbFlavor() {
-        String oldFlavor = getHerbFlavor();
-        String newFlavor =
-                CommandLine.getInstance().getSwitchValue(ChromeSwitches.HERB_FLAVOR, null);
-        sCachedHerbFlavor = newFlavor;
-        Log.d(TAG, "Caching Herb flavor: " + sCachedHerbFlavor);
-
-        if (!TextUtils.equals(oldFlavor, newFlavor)) {
-            Context context = ApplicationStatus.getApplicationContext();
-            ChromePreferenceManager.getInstance(context).writeString(HERB_FLAVOR_KEY, newFlavor);
-            return true;
-        }
-        return false;
+    public void setCachedHerbFlavor(String flavor) {
+        writeString(HERB_FLAVOR_KEY, flavor);
     }
 
     /**
      * Writes the given int value to the named shared preference.
      *
      * @param key The name of the preference to modify.
      * @param value The new value for the preference.
      */
     private void writeInt(String key, int value) {
         SharedPreferences.Editor ed = mSharedPreferences.edit();
         ed.putInt(key, value);
         ed.apply();
     }
 
     /**
      * Writes the given String to the named shared preference.
      *
      * @param key The name of the preference to modify.
      * @param value The new value for the preference.
      */
     private void writeString(String key, String value) {
         SharedPreferences.Editor ed = mSharedPreferences.edit();
         ed.putString(key, value);
         ed.apply();
     }
 }