Enable spare RenderProcessHost to be preinitialized.

chrome/android/java/src/org/chromium/chrome/browser/ChromeFeatureList.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;
 
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.MainDex;
 import org.chromium.base.library_loader.LibraryLoader;
@@ skipping 179 matching lines @@
     public static final String MATERIAL_DESIGN_INCOGNITO_NTP = "MaterialDesignIncognitoNTP";
     public static final String NEW_PHOTO_PICKER = "NewPhotoPicker";
     public static final String NO_CREDIT_CARD_ABORT = "NoCreditCardAbort";
     public static final String NTP_CONDENSED_LAYOUT = "NTPCondensedLayout";
     public static final String NTP_CONDENSED_TILE_LAYOUT = "NTPCondensedTileLayout";
     public static final String NTP_FOREIGN_SESSIONS_SUGGESTIONS = "NTPForeignSessionsSuggestions";
     public static final String NTP_LAUNCH_AFTER_INACTIVITY = "NTPLaunchAfterInactivity";
     public static final String NTP_OFFLINE_PAGES_FEATURE_NAME = "NTPOfflinePages";
     public static final String NTP_SHOW_GOOGLE_G_IN_OMNIBOX = "NTPShowGoogleGInOmnibox";
     public static final String NTP_SNIPPETS_INCREASED_VISIBILITY = "NTPSnippetsIncreasedVisibility";
+    public static final String OMNIBOX_SPARE_RENDERER = "OmniboxSpareRenderer";
     public static final String PAY_WITH_GOOGLE_V1 = "PayWithGoogleV1";
     public static final String SERVICE_WORKER_PAYMENT_APPS = "ServiceWorkerPaymentApps";
     public static final String SITE_NOTIFICATION_CHANNELS = "SiteNotificationChannels";
     public static final String SPANNABLE_INLINE_AUTOCOMPLETE = "SpannableInlineAutocomplete";
     public static final String TAB_REPARENTING = "TabReparenting";
     public static final String VIDEO_PERSISTENCE = "VideoPersistence";
     public static final String VR_BROWSING_FEEDBACK = "VrBrowsingFeedback";
     public static final String VR_CUSTOM_TAB_BROWSING = "VrCustomTabBrowsing";
     public static final String VR_SHELL = "VrShell";
     public static final String WEB_PAYMENTS = "WebPayments";
     public static final String WEB_PAYMENTS_MODIFIERS = "WebPaymentsModifiers";
     public static final String WEB_PAYMENTS_SINGLE_APP_UI_SKIP = "WebPaymentsSingleAppUiSkip";
     public static final String WEBVR_AUTOPRESENT = "WebVrAutopresent";
     public static final String WEBVR_CARDBOARD_SUPPORT = "WebVRCardboardSupport";
     public static final String XGEO_VISIBLE_NETWORKS = "XGEOVisibleNetworks";
 
     private static native boolean nativeIsInitialized();
     private static native boolean nativeIsEnabled(String featureName);
     private static native String nativeGetFieldTrialParamByFeature(
             String featureName, String paramName);
     private static native int nativeGetFieldTrialParamByFeatureAsInt(
             String featureName, String paramName, int defaultValue);
     private static native double nativeGetFieldTrialParamByFeatureAsDouble(
             String featureName, String paramName, double defaultValue);
     private static native boolean nativeGetFieldTrialParamByFeatureAsBoolean(
             String featureName, String paramName, boolean defaultValue);
 }