Fall back to shortcut A2HS when Phonesky is out of date or unavailable.

chrome/browser/android/webapk/chrome_webapk_host.h

 // Copyright 2016 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_WEBAPK_CHROME_WEBAPK_HOST_H_
 #define CHROME_BROWSER_ANDROID_WEBAPK_CHROME_WEBAPK_HOST_H_
 
 #include <jni.h>
 
+#include "base/callback.h"
 #include "base/macros.h"
 
 // ChromeWebApkHost is the C++ counterpart of org.chromium.chrome.browser's
 // ChromeWebApkHost in Java.
 class ChromeWebApkHost {
  public:
+  using CanUseGooglePlayInstallApiCallback = base::Callback<void(bool)>;
+
   // Registers JNI hooks.
   static bool Register(JNIEnv* env);
 
   // Returns whether the "enalbe-webapk" is turned on.
   static bool AreWebApkEnabled();
 
+  // Returns whether the Google Play Install is allowed.
+  static bool CanUseGooglePlayToInstallWebApk();
+
+  // Checks whether Google Play Install API is available. The callback can be
+  // called synchronously.
+  static void CanUseGooglePlayInstallApi(
+      const CanUseGooglePlayInstallApiCallback& Callback);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ChromeWebApkHost);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPK_CHROME_WEBAPK_HOST_H_