title: Register flutter web plugins manually
body: <p>Flutter is generating a file <code>generated_plugin_registrant.dart</code> for web project that looks like</p>
  
  <pre class="lang-dart prettyprint-override"><code>void registerPlugins(PluginRegistry registry) {
    FirestoreWeb.registerWith(registry.registrarFor(FirestoreWeb));
    FirebaseAuthWeb.registerWith(registry.registrarFor(FirebaseAuthWeb));
    FirebaseCoreWeb.registerWith(registry.registrarFor(FirebaseCoreWeb));
    GoogleSignInPlugin.registerWith(registry.registrarFor(GoogleSignInPlugin));
    SharedPreferencesPlugin.registerWith(registry.registrarFor(SharedPreferencesPlugin));
    UrlLauncherPlugin.registerWith(registry.registrarFor(UrlLauncherPlugin));
    registry.registerMessageHandler();
  }
  </code></pre>
  
  <p>I would like to disable some plugins for the web only (FirestoreWeb is crashing because I don't have the proper web initialization and I don't want to). It is not possible to modify it but I would like to know if it is possible to have a custom <code>registerPlugins()</code> that could override the default behavior where I could manually register the plugin I want or disable in <code>pubspec.yaml</code> some plugin for the web only.</p>