Fall back to legacy add to homescreen behavior on non-GMS device or GMS isn't availabe.

chrome/browser/android/webapk/webapk_installer.cc

 // 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.
 
 #include "chrome/browser/android/webapk/webapk_installer.h"
 
 #include "base/android/build_info.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/android/path_utils.h"
@@ skipping 292 matching lines @@
       env, java_ref_, java_file_path, java_package_name);
 }
 
 bool WebApkInstaller::StartUpdateUsingDownloadedWebApk(
     JNIEnv* env,
     const base::android::ScopedJavaLocalRef<jstring>& java_file_path) {
   return Java_WebApkInstaller_updateAsyncFromNative(
       env, java_ref_, java_file_path);
 }
 
-bool WebApkInstaller::HasGooglePlayWebApkInstallDelegate() {
+bool WebApkInstaller::CanUseGooglePlayInstallService() {
   JNIEnv* env = base::android::AttachCurrentThread();
-  return Java_WebApkInstaller_hasGooglePlayWebApkInstallDelegate(
+  return Java_WebApkInstaller_canUseGooglePlayInstallService(
       env, java_ref_);
 }
 
 bool WebApkInstaller::InstallOrUpdateWebApkFromGooglePlay(
     const std::string& package_name,
     int version,
     const std::string& token) {
   webapk_package_ = package_name;
 
   JNIEnv* env = base::android::AttachCurrentThread();
@@ skipping 90 matching lines @@
     OnFailure();
     return;
   }
 
   GURL signed_download_url(response->signed_download_url());
   if (!signed_download_url.is_valid() || response->package_name().empty()) {
     OnFailure();
     return;
   }
 
-  if (HasGooglePlayWebApkInstallDelegate()) {
+  if (CanUseGooglePlayInstallService()) {
     int version = 1;
     base::StringToInt(response->version(), &version);
     if (!InstallOrUpdateWebApkFromGooglePlay(
         response->package_name(), version, response->token())) {
       OnFailure();
     }
     return;
   }
 
   OnGotWebApkDownloadUrl(signed_download_url, response->package_name());
@@ skipping 178 matching lines @@
 
 void WebApkInstaller::OnSuccess() {
   finish_callback_.Run(true, webapk_package_);
   delete this;
 }
 
 void WebApkInstaller::OnFailure() {
   finish_callback_.Run(false, webapk_package_);
   delete this;
 }