[Extensions Bindings] Introduce a supportsLazyListeners property

extensions/renderer/bindings/api_binding_js_util.h

 // Copyright 2017 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 EXTENSIONS_RENDERER_BINDINGS_API_BINDING_JS_UTIL_H_
 #define EXTENSIONS_RENDERER_BINDINGS_API_BINDING_JS_UTIL_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 44 matching lines @@
                                      const std::string& event_name,
                                      v8::Local<v8::Function> massager);
 
   // A handler to allow custom bindings to create custom extension API event
   // objects (e.g. foo.onBar).
   // TODO(devlin): Currently, we ignore schema. We may want to take it into
   // account.
   void CreateCustomEvent(gin::Arguments* arguments,
                          v8::Local<v8::Value> v8_event_name,
                          v8::Local<v8::Value> unused_schema,
-                         bool supports_filters);
+                         bool supports_filters,
+                         bool supports_lazy_listeners);
 
   // Creates a new declarative event.
   void CreateCustomDeclarativeEvent(
       gin::Arguments* arguments,
       const std::string& event_name,
       const std::vector<std::string>& actions_list,
       const std::vector<std::string>& conditions_list,
       int webview_instance_id);
 
   // Invalidates an event, removing its listeners and preventing any more from
@@ skipping 38 matching lines @@
   ExceptionHandler* const exception_handler_;
 
   binding::RunJSFunction run_js_;
 
   DISALLOW_COPY_AND_ASSIGN(APIBindingJSUtil);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_BINDINGS_API_BINDING_JS_UTIL_H_