[Reland] Refactor WebappRegistry into a singleton instance.

chrome/browser/android/chrome_jni_registrar.cc

Index: chrome/browser/android/chrome_jni_registrar.cc
diff --git a/chrome/browser/android/chrome_jni_registrar.cc b/chrome/browser/android/chrome_jni_registrar.cc
index 5cd06311d9cca0beeadfc0dac7ccabc3dc560057..f28f69167b729614f1dd3d460ec3cd88d9df2b7a 100644
--- a/chrome/browser/android/chrome_jni_registrar.cc
+++ b/chrome/browser/android/chrome_jni_registrar.cc
@@ -103,7 +103,6 @@
 #include "chrome/browser/android/webapk/webapk_installer.h"
 #include "chrome/browser/android/webapk/webapk_update_manager.h"
 #include "chrome/browser/android/webapps/add_to_homescreen_manager.h"
-#include "chrome/browser/android/webapps/webapp_registry.h"
 #include "chrome/browser/autofill/android/personal_data_manager_android.h"
 #include "chrome/browser/dom_distiller/dom_distiller_service_factory_android.h"
 #include "chrome/browser/dom_distiller/tab_utils_android.h"
@@ -382,7 +381,6 @@ static base::android::RegistrationMethod kChromeRegisteredMethods[] = {
     {"WarmupManager", RegisterWarmupManager},
     {"WebApkInstaller", WebApkInstaller::Register},
     {"WebApkUpdateManager", WebApkUpdateManager::Register},
-    {"WebappRegistry", WebappRegistry::RegisterWebappRegistry},
     {"WebContentsFactory", RegisterWebContentsFactory},
     {"WebsitePreferenceBridge", RegisterWebsitePreferenceBridge},
     {"WebsiteSettingsPopupAndroid",