Make chrome://flags control whether the WebAPK feature is on

chrome/browser/android/chrome_feature_list.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_CHROME_FEATURE_LIST_H_
 #define CHROME_BROWSER_ANDROID_CHROME_FEATURE_LIST_H_
 
 #include <jni.h>
 
 #include "base/feature_list.h"
 
 namespace chrome {
 namespace android {
 
 // Alphabetical:
 extern const base::Feature kAndroidPayIntegrationV1;
 extern const base::Feature kCCTExternalLinkHandling;
 extern const base::Feature kCCTPostMessageAPI;
 extern const base::Feature kChromeHomeFeature;
 extern const base::Feature kContextualSearchSingleActions;
 extern const base::Feature kDownloadsUiFeature;
 extern const base::Feature kImportantSitesInCBD;
+extern const base::Feature kImprovedA2HS;
 extern const base::Feature kNoCreditCardAbort;
 extern const base::Feature kNTPFakeOmniboxTextFeature;
 extern const base::Feature kNTPOfflinePagesFeature;
 extern const base::Feature kPhysicalWebFeature;
 extern const base::Feature kPhysicalWebIgnoreOtherClientsFeature;
 extern const base::Feature kSpecialLocaleFeature;
 extern const base::Feature kSpecialLocaleWrapper;
 extern const base::Feature kTabReparenting;
 extern const base::Feature kUserMediaScreenCapturing;
-extern const base::Feature kWebApks;
 extern const base::Feature kWebPaymentsModifiers;
 
 bool RegisterChromeFeatureListJni(JNIEnv* env);
 
 }  // namespace android
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_CHROME_FEATURE_LIST_H_