Chrome talks to Play to install WebAPKs.

chrome/browser/android/webapk/webapk_installer.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_WEBAPK_INSTALLER_H_
 #define CHROME_BROWSER_ANDROID_WEBAPK_WEBAPK_INSTALLER_H_
 
 #include <jni.h>
 #include <memory>
 
@@ skipping 125 matching lines @@
   // request the WebAPK server responds with the URL of the generated WebAPK.
   // |webapk| is the proto to send to the WebAPK server.
   void SendUpdateWebApkRequest(std::unique_ptr<webapk::WebApk> webapk_proto);
 
   // Sends a request to WebAPK server to create/update WebAPK. During a
   // successful request the WebAPK server responds with the URL of the generated
   // WebAPK.
   void SendRequest(std::unique_ptr<webapk::WebApk> request_proto,
                    const GURL& server_url);
 
+  // Called when the package name of the WebAPK is available and the install
+  // or update request goes through Play Store.

[pkotwicz, 2016/12/02 02:24:00]

How about: "and the install or update request should be handled by Google Play."

[Xi Han, 2016/12/02 20:45:37]

Done.

+  void InstallOrUpdateWebApkFromPlayStore(const std::string& package_name,
+                                          int version,
+                                          const std::string& token);
+
   // Called with the URL of generated WebAPK and the package name that the
   // WebAPK should be installed at.
   void OnGotWebApkDownloadUrl(const GURL& download_url,
                               const std::string& package_name);
 
   // Downloads the WebAPK from the given |download_url|.
   void DownloadWebApk(const base::FilePath& output_path,
                       const GURL& download_url,
                       bool retry_if_fails);
 
@@ skipping 80 matching lines @@
   // Points to the Java Object.
   base::android::ScopedJavaGlobalRef<jobject> java_ref_;
 
   // Used to get |weak_ptr_|.
   base::WeakPtrFactory<WebApkInstaller> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebApkInstaller);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPK_WEBAPK_INSTALLER_H_