Chrome talks to Play to install WebAPKs.

chrome/browser/android/webapk/webapk_installer.h

Index: chrome/browser/android/webapk/webapk_installer.h
diff --git a/chrome/browser/android/webapk/webapk_installer.h b/chrome/browser/android/webapk/webapk_installer.h
index c24a66886f1d919d5d86d9a41f6c0baaeb25b304..73e1a5ecf407db77faa9f6fc751630808923afff 100644
--- a/chrome/browser/android/webapk/webapk_installer.h
+++ b/chrome/browser/android/webapk/webapk_installer.h
@@ -105,6 +105,16 @@ class WebApkInstaller : public net::URLFetcherDelegate {
       JNIEnv* env,
       const base::android::ScopedJavaLocalRef<jstring>& java_file_path);
 
+  // Returns whether installing WebAPKs using Google Play is enabled.
+  virtual bool HasGooglePlayWebApkInstallDelegate();
+
+  // Called when the package name of the WebAPK is available and the install
+  // or update request is handled by Google Play.
+  virtual bool InstallOrUpdateWebApkFromGooglePlay(
+      const std::string& package_name,
+      int version,
+      const std::string& token);
+
   // Called when the request to install the WebAPK is sent to Google Play.
   void OnSuccess();